Are they really my parents?

If both of my parents have O positive blood, is it possible for me to have O negative blood? I have been told that it is not possible, that one parent would have to have the negative factor. I have been researching this question for some time with no good answer. I would really appreciate your help in answering this.
Debbie Howlett – Farmington, New Mexico

Dr. Greene’s Answer:

Genetics can be so confusing! I can easily see how after much research the issue about your parents would still appear murky.

The modern science of genetics had its start in 1866 when an Austrian monk named Gregor Mendel provided a simple yet powerful description of how traits are passed on from one generation to another. Mendel’s work was unappreciated until 1900 — more than fifteen years after his death. In his initial formulation, he described how sexual beings get two genes for each trait, one from each parent. The trait expressed, or visible, is a result of the interplay between these two genes. Specifically, he recognized that some genes are dominant and some are recessive. If you have one copy of a dominant gene you will express that trait, regardless of the other gene. In order to express a recessive trait you must have two recessive genes.

Mendel’s first experiments, though simple, were quite profound. He worked with peas, which had easily distinguishable traits, such as green versus yellow seeds. Each pea has two seed-color genes, one from each parent. The peas with two yellow genes were yellow. Those with a yellow and a green gene were also yellow; only those with two green genes turned out to be to green. Thus yellow was dominant over the recessive green gene.

The situation with human blood genetics is far more complex, since at each point there are multiple possible characteristics. Nevertheless, the genetics of human blood is far better understood than that of any other human tissue. While there are rare exceptions, the following information on blood types applies to most people.

First, let’s look at the ABO blood types. Each person receives an A, B, or O gene from each parent. In this system, the A and B genes are co-dominant and the O gene is recessive. Thus, a person whose genetic type is either AA or AO will have blood type A, those with genetic type BB or BO will have blood type B, and only those genetic type OO will have blood type O. This means that a child with type O blood could have parents with type A, type B, or type O blood (but not with type AB). Conversely, if two parents both have type O blood, all their children will have type O blood.

Another medically important blood type is described in the Rh system. These genes were first discovered in the rhesus monkey, hence the designation Rh. The Rh system is actually far more complex than the ABO system in that there are 35 different possibilities that one could inherit from each parent. These, however, are roughly grouped into positive and negative types. In this system the positive are dominant over the negative. If your genetic type is ++ or +-, your blood type will be Rh positive. Only if your genetic type is — will you be Rh negative. This means that if both parents have Rh+ blood with the +- genes, they could have children who are ++, +-, or –. In other words, their children could be either Rh positive or Rh negative. Children who are Rh negative can have parents who are either Rh positive or Rh negative.

Two parents who have O positive blood could easily have a child who is O negative. In fact, most children who are O negative have parents who are positive, since the +- combination is so much more common than the — combination.

As it turns out, there are more than a dozen complete blood group systems other than the ABO system and the Rh system. This makes great precision possible in looking at inheritance and family trees.

There is no reason, based on your blood type, to suspect that your parents might not really be your parents. If questions linger for other reasons, specific tests are available through blood banks and private laboratories that can settle the issue. These tests are commonly known as paternity and maternity DNA testing (for father and mother respectively). Given the billions of unique people on this planet, the power and precision of genetic testing are amazing.

Dr. Alan Greene

Dr. Greene is a practicing physician, author, national and international TEDx speaker, and global health advocate. He is a graduate of Princeton University and University of California San Francisco.

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  1. Lovely

    Hi. I always thought I had an O blood type but getting hospitalized after an accident revealed I was actually B+. If my mom is O+ and my dad is O+ and all my siblings are O+, how did I become B+?

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    • Hi Lovely,

      Our current understanding of genetics is that it is not possible for two parents with type O blood to have a child with type B blood. If both your parents are O+, they could have children with O+ or O- blood, but it’s not uncommon for blood types to be different than they are thought. It is wise to have all your blood retested before jumping to any conclusions.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  2. Bethany

    Hi Dr. Greene,

    Is it possible for a mother and father that both have type B blood to have a child is with type A blood and another child with type O blood?

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    • Hi Bethany,

      Our current understanding of genetics is that it is not possible two parents with type B blood to have a child with type A blood, but they can have a child with type O blood.

      It’s not uncommon for blood types to be different than they are thought. It is wise to have both parents and the child with type B blood retested before jumping to any conclusions.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  3. Gautam

    Hello Dr.
    I just want to ask, can a mother with AB + blood group give birth to O + in any case??

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    • Gautam,

      Our current understanding of genetics is that it is not possible for one parent to be AB+ parent to have a child that is O+.

      Can a mother with AB+ blood give birth to a child with O+ blood in any case? There is a very rare blood type, called Bombay, that falls outside the ABO system. If a person has that type, he or she shows up as type O, but both parents must be carriers. I don’t think that would fit with an AB blood type.

      In this case, it would be wise to have all your blood retested. It’s not uncommon for blood types to be different than they are thought. DNA paternity tests are still accurate (99.999%) with type hh blood and are considered the only accurate test for paternity.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  4. Rox

    Mother O-. Two kids AB-, other three kids A-. How is it possible that she is the mother of the AB- kids?? Her blood has been tested multiple times. She had to have a transfusion when she gave birth to my oldest sister and they had to have type O- transported in because they did not have any in the local blood banks. (1959)
    I wonder if she is really type A but keeps retesting as type O for some reason. Is that possible?? Maybe the transfusion worked out because O- is the universal donor. Scratching my head.

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    • Rox,

      That is very curious. There is a very rare blood type (0.0004% or about 4 per million in the general population) known as the Bombay Blood type. In some places such as Mumbai (which was formerly called Bombay), the occurrences can be as high as 0.01% or 1 in 10,000. This group does not fall into the ABO system and the usual tests for ABO blood show them as group O.

      The Bombay blood type is usually only found in small communities where there are other people with the Bombay or hh blood type. Both parents have to be h carriers, though a parent can be a carrier without actually having Bombay type blood.

      If you suspect your mother may have the Bombay blood type she can talk to her doctor about a specialized test for this blood type as it does not show up using the normal ABO blood type tests.

      DNA paternity (in this case maternity) tests are still accurate (99.999%) with type hh blood and are considered the only accurate test for paternity / maternity.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  5. Robert work

    Mother is o positive dad is a negative, can child be o positive

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    • Hi Robert,

      Yes! If one parent is O+ and the other is A-, their children can be O+.

      Here is a list of the blood types their children can have:
      — O+
      — O-
      — A+
      — A-

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  6. Kim

    If my mom is A+ and my father O-then is it possible for them to have a child with AB?

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    • Hi Kim,

      Thanks for your question.

      Our current understanding of genetics is that it is not possible for one parent to have type A+ blood, the other parent to be O- and their child to have type AB blood. An AB child can only have parents that are A and B, or A and AB, or B and AB.

      It is wise to have all three blood types retested. It’s not uncommon for blood types to be different than they are thought.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  7. kat

    Hello, can i ask if my father was AB neg and my mother was 0 positive why I have 0 neg blood, both my sisters are A neg and B neg, this makes my dad not my biological father right???.

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    • Hi Kat,

      Thanks for writing in.

      You are correct that a parent with type AB blood can’t have a child with type O blood. But it’s not uncommon for blood types to be different than they are thought. It is wise to have all your blood retested before drawing any conclusions.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  8. Alok

    Hi
    Can A- father and AB+ mother have o+ child

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    • Dear Alok,

      This is a very interesting question. If a parent has A- blood, he or she can have a child with O+ blood, if the other parent is Rh+. But a parent with AB+ blood can not have a child with O+ blood. A person with AB blood can only have children with A, B or AB blood (depending on the blood type of the other parent).

      It’s likely wise to have all your blood retested. It’s not uncommon for blood types to be different than they are thought.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  9. Ann

    Hi There ,

    Wife is o+ , husband is o+ , i delivered twins and records shows their blood type is b+.
    Is that possible ? first born and 2nd born are both o+. We are both certain that these twins are “ours”

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    • Hi Ann,

      If two parents have O+ blood, their children can only be O+ or O-. It is wise to have all your blood retested. It’s not uncommon for blood types to be different than they are thought.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  10. Puru

    Hello

    My brother has AB+ blood group though both my parents have B+ blood groups. I called a DNA testing centre and they said that the child can have AB+ but not AB-. Is it possible? How does it happen? Can you refer a study explaining this phenomena?

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    • Hello Puru,

      I can see your need for clarification.

      Our current understanding of genetics is a person with AB blood type has to get the A from one parent and the B from the other. That means the two parents can be:
      — AB and AB or
      — AB and B or
      — AB and A or
      — A and B
      — But both parents cannot be type B

      The Rh system is completely different from the ABO system. Rh+ simply means the D Antigen is present in the blood. Rh- means it is not. Two Rh+ parents do not necessarily pass down the D Antigen, so two Rh+ parents can have a child that is Rh+ or Rh-. Since the D Antigen isn’t present in people who are Rh-, two Rh- parents can’t have a child that is Rh+.

      Perhaps what the person at the DNA company meant was two B+ parents could have a child that is Rh-, but they couldn’t have a child that has type AB blood.

      If that doesn’t answer your question, I’m afraid you’ll have to get back in touch with the DNA company that gave you that information.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  11. Rhiannon

    Hi,I have 2 potential dads and hope you can help,my mother is o+ and one potential is o+ too,I am b-.This man cannot be my biological father can he?

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    • Hi Rhiannon,

      You are correct. If your mom has O+ blood and if you have B- blood, your father cannot be O+ (or O-). If your mom has O+ blood and if you have B- blood, your father could have B-, B+, AB- or AB+ blood.

      It’s not out of the question that your blood types are not what you think they are. It’s wise to have all blood types retested before jumping to any conclusions.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  12. Cheryl

    I am RH negative and so is my mother. My father is AB positive. I have been told lately it is impossible for him to be my father. Is this correct?
    Cheryl

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    • Hi Cheryl,

      Thanks for your question.

      You’ve provided your father’s blood type (AB+) but only your mother and your Rh status (-). With this limited information I can’t address your question fully, but if your mother is Rh- and your father is Rh+, their child could be Rh-. In fact, two Rh+ parents can have a child that is Rh-.

      You mention that your father has type AB blood. If that is the case, he can not have a child with type O blood, but he could have a child with type A, B or AB, depending on the blood type of the mother.

      I hope that’s helpful.
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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      • Cheryl

        My mom and I are both group O RH negative and my dad is AB positive. Is it possible he isn’ t my father. I have been told recently it isn’t possible.

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        • Hi again Cheryl,

          Our current understanding of genetics is that it is not possible for one parent to be AB+, the other parent to be O- and their child to be O-. An AB parent can only have children who are A, B or AB.

          It’s not uncommon for blood types to be different than they are thought so it’s wise to have all your blood retested. If there are still questions, a DNA paternity test is the next step.

          I hope that helps.
          Best, @MsGreene
          Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  13. Cheryl

    My niece is O negative and she gave birth to an AB+ son. The hospital double cked it at birth, since they say that is impossible. We have many witnesses to the birth!! lol Her husband is AB-. How did that happen?

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    • Hi Cheryl,

      Since all blood types have been rechecked, it would be wise to have a DNA paternity (in this case maternity) test run. If the child never left her side in the hospital, this may not be necessary, but it’s still an inexpensive way to double check. If the maternity test comes back that she is indeed the mother, it’s time to look at some very rare blood types that our current ABO testing system can’t detect. This would mean working with physicians and labs that specialize in these rare tests and outcomes and could be quite expensive.

      I hope that’s helpful.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  14. Divya shree

    Hello…. I am divya….my husband blood group is.B+, My blood group is O+, so..my son’s blood group is A+ .How its possible?

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    • Hello Divya,

      Our current understanding of genetics is that it is not possible for one parent to be B+, the other parent to be O+ and their child to be O+. A parent with B+ blood and a parent with O+ blood can only have children with B+, B-, O+ or O- blood.

      It is wise to have all your blood retested. It’s not uncommon for blood types to be different than they are thought.

      If you are sure you know who the father is, and if the blood tests still come back with the same outcomes, you might consider looking into a very rare blood type called the Bombay Blood type. Our standard blood tests can not test for this type, so they show up with the wrong blood type. If you’d like to know more about that, please let me know.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  15. Natalija

    Dad:B+
    Mom:A+
    Me:O-
    I don’t know anybody in my family that has Rh- blood bedside me.I’ve read that the chance of this happening is 6,25% and we don’t know my sister’s blood type.Also I know that I am 100% European.
    Can someone please provide me more information about this.

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    • Hi Natalija,

      Thanks for writing in.

      Blood types are comprised of two alleles. The most common (by far) are A, B, and O.
      — If a person has type A blood he or she has at least one A allele. He or she can have two A alleles (AA) but can also have one A and one O (AO). Both are called type A blood.
      — If a person has type B blood he or she has at least one B allele. He or she can have two B alleles (BB) but can also have one B and one O (BO). Both are called type B blood.

      Rh+ means a person is positive for the D antigen. Rh- means a person does not have the D antigen.
      — If a person is Rh+, he or she can have a child that is Rh+ or Rh-.
      — If a person is Rh-, he or she can only have a child that is Rh+ if the other parent is Rh+.
      — Two parents with Rh- blood can not have a child with Rh+ blood.
      — Two parents with Rh+ blood can have children with Rh+ or Rh- blood.

      What all this means is if your mom is A+ and if your dad is B+ they could have a child who is O- and that would be perfectly normal. In fact, each of their children has a 6.25% chance of having O- blood.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  16. Rutvi Anil Kalavadiya

    if the parents have a particular blood group.explain why does the children have different blood group

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    • Hi Rutvi,

      Thanks for writing in.

      Can you give me an example of each parent’s blood group and the child’s blood group so I will better understand your question?

      Thanks, MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  17. Abdoul

    Hello, I have B, my wife is O . I know we can ha both O or B. My 2 kids are B. so I guess I am BB. My 3rd child is O and I am confused. I can not also be BO and BB. My question is, can 2 parents with B and O have kids with both O and B at the same time?

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    • Hello Abdoul,

      Let me see if I’m understanding your question:

      You have blood type B, your wife has blood type O, you have two children with blood type B and one with blood type O. You are wondering if it’s possible that you are the father of all three children.

      If I understand it correctly, the answer is YES! It would mean that you do have one B allele and one O allele in your blood type.

      This outcome is common and totally within reason. In fact, there is a 25% chance each of your children will have blood type O and 75% chance each of your children will have type B blood.

      I hope this is helpful.

      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  18. Angela

    My sister has always been slightly concerned as to wether she is our full sister. Our mothers blood group is Rh O+ and our fathers is Rh O- ….. me and my youngest sister are Rh O- but our middle sister (who is currently pregnabt) has found out she is Rh OD +….I’ve never heard of this blood group.

    It would mean absolutely nothing if it wasn’t the outcome she wanted..

    But concerns are there and we want to put them to rest.

    Thank you

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    • Hi Angela,

      Thanks for writing in.

      It would be interesting to look at the lab reports for all your blood types. Likely they say something like “O+” or “O, D+” or “O, Rh+”. These all mean the same thing. “O+” is just a short way of saying the blood type is O, and the blood is + for the D antigen. It’s called Rh+ because the discovery of the D antigen was made in rhesus monkeys.

      The bottom line is if one parent is O+ and the other is O-, they can have children who are O+ or O-. Your sister’s blood type test doesn’t rule out your father as her biological father. Neither does it prove that he is. Only DNA paternity tests are considered definitive in determining paternity.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  19. Reg

    Question please help. I have been told I have A negative blood. My father for sure has O negative and my mother had O, she has passed so I do not know for sure. My maternal grandfather had A negative. Is it possible that i have A negative with 2 O parents?

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    • Reg,

      Thanks for writing in.

      Above you ask if you have A- blood. The easiest thing to do to determine your blood type is to be re-tested by a trusted lab.

      But what I think you’re really asking is “if I have A- blood, my father has O- and I think my mother had type O blood, are they really my parents?” You will likely have a difficult time sussing this all out since your mother is no longer living and you can’t confirm her blood type. But let’s break it down —

      — You could be Rh- even if both parents were / are Rh+, so that’s not an issue.
      — For you to have type A blood, one parent has to be type A or type AB. Since your grandfather is believed to have had type A blood, there is further evidence that your mother could have had type A blood.

      Typically, maternity is easy to prove with photos. There is a very rare occurrence of “switched at birth” scenarios. If you think that is the issue, you could try getting DNA testing from your father since it would be extremely unlikely for him to be the father of two children born in the same hospital on the same day and switched at birth. That would make the record books, I would think.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  20. Christina

    I have B- blood (I have had 2 children, and blood typing for c-sections so I have a card saying I am B-), but both my parent say they are O-. My mother donates blood monthly so I don’t think she is inaccurate. My father has had leukemia, so I don’t think he is inaccurate. Is someone possibly not telling me something?

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    • Christina,

      Thanks for writing in.

      Our current understanding of genetics is that it is not possible for two O- parents to have a B- child.

      If there is a question about paternity (or maternity), a DNA paternity test is the only test considered definitive. They are fairly inexpensive, can be ordered online, taken in the privacy of your own home, mailed in, and results received by mail. They are considered 99.999% accurate.

      Typically the first step is an open conversation with your parents.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  21. moeby

    Hello, We seem to have some things not adding up.
    Dad O+ , Mom assume AB+, daughter 1-A-, daughter 2-AB+, daughter 3, B+
    we are getting a confirmation on both mom and dad but all daughters are 100% sure and dad 99% sure. how can this be

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    • Moeby,

      Thanks for writing in.

      As I’m sure you’ve guessed, if one parent is AB+ and if the other is O+ they can have kids who are A+, A-, B+, B-, O+ or O-. They can not have a child who is AB+ or AB-.

      If there is a question of paternity (or maternity), a DNA paternity test is the only test considered definitive. They are fairly inexpensive, can be ordered online, taken in the privacy of your own home, mailed in, and results received by mail. They are considered 99.999% accurate.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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      • Lori Rustin

        If kids are now adults and if they were, or are, part of a fairly happy family, does it help anyone to open pandora’s box?

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        • Hi Lori,

          Thanks for weighing in.

          You raise a valid point, but there are times when family history provides vital health information. Adult children need to weigh the potential damage that can be done to the family when raising these questions, but there are times for this discovery. Unfortunately, the time is not after a parent has passed away and discovery is no longer a simple DNA paternity test.

          Please let me know what you think.

          Best, @MsGreene
          Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  22. David

    Am David, my blood group is O negative and my wife’s blood group is A Positive. Can we have a child?

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    • Hi David,

      Sounds like you’ve heard of a condition that can occur when one parent is Rh+ and the other is Rh-. Thankfully for you, there is only a problem when the mother is Rh- and the father is Rh+ and not the other way around.

      Dr. Greene explains it fully in his article How To Determine and Manage Rh Incompatibility.

      To answer your specific question, your two blood types should not be an issue with having children.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  23. Charles

    do both parents have to be O positive cmv negitive for me to have it

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  24. Arun Kumar A S

    My father and mother has O+ and O- blood group respectively and I have AB+ blood group. Is this possible?

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    • Dear Arun,

      Our current understanding of genetics is that it is not possible for one parent to have O+ blood, the other parent to have O- blood and a child their child to have AB+ blood.

      It is wise to have all your blood retested. It’s not uncommon for blood types to be different than they are thought. After repeat blood type tests, if there is a parentage question, a DNA paternity test is the only test considered definitive. They are fairly inexpensive, can be ordered online, taken in the privacy of your own home, mailed in, and results received by mail. They are considered 99.999% accurate.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  25. Julie

    My blood type is negative A my moms blood type is B positive and my fathers blood type is negative O. Can you please just tell me with a yes or no answer if this is possible? I don’t wanna say anything unless it’s not possible please give me a straight answer

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    • Hi Julie,

      First, keep in mind it’s not uncommon for blood types to be different than they are thought. But, our current understanding of genetics is that it is not possible for one parent to be B+, the other parent to be O- and a child their child to be A-.

      It is wise to have all your blood re-tested. If there is a question, a DNA paternity test is the only test considered definitive. They are fairly inexpensive, can be ordered online, taken in the privacy of your own home, mailed in, and results received by mail. They are considered 99.999% accurate.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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      • Deb

        They are saying a RH positive woman cant have a child with a Rh Negative man and I know this is bs because I have two by an Rh Negative man and I am Rh Positive-it is the other way around-that is what produces a blue baby in the second child if no Rhogam is given to the mother after the first child. Lord what a piece of bs. Rh negative mothers have issues with Rh positive fathers.

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        • Deb,

          You are correct, an Rh- mother can have issues if the father of her baby is Rh+. Dr. Greene explains it here — How To Determine and Manage Rh Incompatibility.

          Best, @MsGreene
          Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  26. Jeevanajyothi

    I am having A negative blood group while my husband was also having A negative blood group but our baby got B positive. Is it possible

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    • Hi Jeevana,

      Thanks for writing in.

      Our current understanding of genetics is that it is not possible for two parents with A- blood type to have a child with B+ blood type.

      It is wise to have all your blood retested. It’s not uncommon for blood types to be different than they are thought.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  27. Emma

    PLEASE HELP! I’ve been trying to figure this out for a year and no one can give me an answer other than, “Well, that’s just not possible. Did your mom cheat?”
    No, she didn’t…and no one was switched at birth either…Genetic testing proves that.

    Okay: Mom is O+ (100% sure), Dad (we assume) is AB+, Sister is B+ (100% sure), Brother is AB+ (100% sure), and I am O+ (100% sure). How is this possible?

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    • Emma,

      Sounds like you’ve done a lot of homework and have heard all the standard answers. A genetic counselor may be able to look at all your tests and provide the answer to your specific situation. There is one very rare combination that could explain it, but I am in no position to say if it applies to you or not.

      The Bombay blood type (0.0004% or about 4 per million in the general population) could fit. In some places such as Mumbai (which was formerly called Bombay) the occurrences can be as high as 0.01% or 1 in 10,000. This group does not fall into the ABO system and the usual tests for ABO blood show them as group O.

      The Bombay blood type is usually only found in small communities where there are other people with the hh blood type. Both parents have to be h carriers, though a parent can be a carrier without actually having Bombay type blood.

      If you suspect you may have the Bombay blood type talk to your doctor about a specialized test for this blood type as it does not show up using the normal ABO blood type tests.

      DNA paternity tests are still accurate (99.999%) with type hh blood and are considered the only accurate test for paternity.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  28. M

    Hello,
    I just found out that I’m O Positive and that my Mother is RH Negative and my dad is A Positive. Is it possible? I wasn’t aware that, could be. Unless I forgot everything I learned in school. Can you please explain?

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    • Hi M,

      There are two parts of the common blood types we’re all used to seeing. Part one is A, B, O or AB. Part two is the presence or absence of the D Antigen. That is called Rh+ or Rh-.

      Above you say you are O+. That means you have two O alleles and the presence of the D Antigen. You say your mom is Rh+, but you don’t say what her ABO type is. You also say your dad is A+.

      If either parent is Rh+, i.e. he or she has the D Antigen, each of their children can be Rh+. In your case it doesn’t matter that your mom is Rh-. If your mom is A, B or O you could be O+.

      Please let me know if you have any other questions.

      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  29. Amalyn

    Hi,
    I am AB neg my husband is O pos, our son is O neg, after everything I read, my understanding is that is that this is not possible. The blood type was confirmed once my son joint the military. Can you possibly have some kind of explanation as to how this is at all possible?
    Thank you in advance for your help and have a blessed day.

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    • Amalyn,

      There is a very rare blood type (0.0004% or about 4 per million in the general population) known as the Bombay Blood type. This group does not fall into the ABO system and the usual tests for ABO blood show them as group O.

      The Bombay blood type is usually only found in small communities where there are other people with the hh blood type. Both parents have to be h carriers, though a parent can be a carrier without actually having Bombay type blood.

      If you suspect you or your child may have the Bombay blood type talk to your doctor about a specialized test for this blood type. It does not show up using the normal ABO blood type tests.

      DNA tests are still accurate (99.999%) with type hh blood and are considered the only accurate test for maternity or paternity. If may be easier to have this test done than to pursue Bombay Blood type testing. DNA tests like this one are fairly inexpensive, can be ordered online, taken in the privacy of your own home, mailed in, and results received by mail.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  30. Kirti Priya

    My mother has A positive blood group and my father has AB positive blood group. Is it possible for me to have O positive blood group?

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    • Hi Kirti,

      Thanks for writing in.

      If one parent has A+ blood and the other parent has AB+ blood each of their children can have A+, A-, B+, B-, AB+ or AB- blood. None of their children can have O+ or O- blood.

      It’s not uncommon for blood types to be different than they are thought. For instance, if one parent is type A+ and the other is B-, their children could be O+ or O-.

      It is wise to have all your blood re-tested before jumping to any conclusions.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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      • Kirti Priya

        I confirmed the blood groups of my parents. My mother has B positive blood group and my father has AB positive blood group and I have O positive blood group. Could it mean I am adopted?

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        • Kirti,

          There is a very rare blood type (0.0004% or about 4 per million in the general population) known as the Bombay Blood type. In some places such as Mumbai (which was formerly called Bombay) the occurrences can be as high as 0.01% or 1 in 10,000. This group does not fall into the ABO system and the usual tests for ABO blood show them as group O.

          The Bombay blood type is usually only found in small communities where there are other people with the hh blood type. Both parents have to be h carriers, though a parent can be a carrier without actually having Bombay type blood.

          If you suspect you may have the Bombay blood type talk to your doctor about a specialized test for this blood type as it does not show up using the normal ABO blood type tests.

          DNA paternity tests are still accurate (99.999%) with type hh blood and are considered the only accurate test for paternity.

          I hope that helps.
          Best, @MsGreene
          Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  31. trevor keough

    if both parents are A+, can there child be ARh -Negative. trevor

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    • Hi Trevor,

      Thanks for writing in.

      Yes, if both parents are A+, they can have children who are A-. They can also have children who are A+, O+ or O-.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  32. Caitlyn Hixson

    Okay so I’m blood type A+ my ex says he’s either A or B and has a child with another woman who’s and the child is type A+ like me. Mine and his child together is O- what would he have to be to father both children a or b?

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    • Hi Caitlyn,

      In your question, you say “…has a child with another woman who’s and the child is type A+ like me.” What is the missing blood type in this sentence?

      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  33. Alex E.

    From my understanding, someone who is Rhesus negative does not carry the Rhesus gene. Does that mean they are a “nonprimate humanoid” ?

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  34. Robert

    Hi Dr.Greene,
    Both parents are O- the child is O+ can this true of the childs blood type?

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    • Hi Robert,

      Thanks for writing in.

      Our current understanding of genetics is that it is not possible for both parents to be O- and their child to be O+. For a child to be Rh+, at least one parent must be Rh+.

      It is wise to have all your blood retested. It’s not uncommon for blood types to be different than they are thought.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  35. alan

    can a mother with RHD negative and father who is O + have a baby that is B + ?

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    • Hi Alan,

      Thanks for writing in.

      If the mother is RhD- and the father is Rh+, they can have a child that is Rh+. If the mother is type AB or B and the father is type O, their child can have type B blood.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  36. Janice

    This is all very confusing. I know that I’m O- (RH-) and my husband is O+. After the birth of our twins, both who are O+ I was given a RH shot. Our next child is O- or that is what we were told. My daughter-in-law says this is not possible. Is she correct?

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    • Hi Janice,

      I agree, this is all very confusing. One of the reasons is the ABO blood groups and Rh factor (-/+) use different rules. You are only concerned about the Rh factor so I’ll address that here.

      If someone is Rh+ he or she is positive for the D antigen. That person may or may not pass it on to his or her children. If neither of the parents have the D antigen present, none of their children can be Rh+. In your case only one parent does have it and can still pass it down, but doesn’t necessarily. That is why the children of one parent who is Rh+ and one parent who is Rh- can have children who are either Rh+ or Rh-.

      I’m so glad you were given Rh shot after your first baby. Dr. Greene writes about How To Determine and Manage Rh Incompatibility. It may be helpful, if you’d like to learn more.

      Thanks for writing in and I hope that helps.

      Best, @MsGreene Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  37. renee

    My father was O+ and my mother was RH-, I am A+, is this correct?? I have always thought I may have been adopted :(

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    • Hi Renee,

      Thanks for writing in.

      Blood types can rule out someone as a parent, but they can’t tell you if a specific person is your parent or not.

      In the example you give, you state your father is O+ and you mother was Rh-, but you don’t state if she was O-, A-, B- or AB-.

      What I can tell you from the scenario you provide is if one parent is Rh+ and the other is Rh-, each of their children could be Rh+ or Rh-. Additionally, if both parents are Rh+, each of their children could be Rh+ or Rh-. But if both parents are Rh-, all of their children will be Rh-.

      Bottomline: from the information you have, it’s possible the people who raised you as their daughter are you biological parents, but it’s not proven that they are.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  38. Elaine

    If I am O+ or O- ( can’t remember) & my childs father is O+ can she be A+?

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    • Hi Elaine,
      Thanks for writing in.
      If both parent have type O blood, all their children will have type O blood, but if one parent has type O blood and the other has either type A or type AB blood, their children could have type A blood.
      I hope that helps.
      Best, @MsGreene Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  39. Trinity

    If my mother is A+ and father is o+/o- then what can I be?

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    • Cheryl Greene

      Hi Trinity,

      Thanks for writing in.

      If one parent is A+ and if the other parent is O+/- their child could be A+, A-, O+ or O-. Two Rh+ parents can still have an Rh- child, but two Rh- parents can not have an Rh+ child.

      Please let me know if you’d like further explanation.

      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  40. Larry Ambrose

    I am Blood Type B Negative. My Wife is also B Negative. We have 4 Children(3 Daughters, 1 Son) . Should(must) all 4 Children have B Negative Type Blood. If not, what are the possibilities of what their Blood Types may be ???

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    • Hi Larry,

      Thanks for writing in.

      If both the mother and the father have Rh- blood, that means they do not carry, and therefore can not pass down, the D antigen. They are negative for D Antigen. That means all their children with be Rh-. If both the mother and the father have type B blood, they each have at least one B allele, could also have an O allele. That means it’s possible that each of their children could be B- or O-.

      Please let me know if you’d like more information.

      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  41. charles

    If child is A or A+ and the mother is B, can a father with type O be the biological father of this mother/child blood type combination?

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    • Hi Charles,

      Thanks for writing in.

      If a child is A or A+ and if the mother is B, the father can be A or AB, but not O. If you’d like an explanation please let me know.

      Please remember that blood types are often not what people think they are, so it’s always wise to have blood types retested before making any assumptions.

      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  42. Julie

    If the mother is A- and the father is A+, can the child be O-?

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    • Julie,

      Thanks for writing in.

      It is possible for one parent to be A-, the other parent to be A+ and their child to be O-. In fact there is a 6.25% chance each child will have type O blood and a 25% chance each child will be Rh-.

      If you’d like an explanation, please let me know.

      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  43. kay

    I have blood group of B rhesus D positive and also my have the same thing but our first daughter is B rhesus D negative. please help me out

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    • Hi Kay,

      There is a bit of information missing from your question. I think you mean both you and your child’s father have B+ blood, but your child has B- and you’d like to know if that’s possible? If that’s what you’re asking, the answer is, yes, that is possible. In fact, there is a 6.35% chance each child of two parents who are Rh+ (or rhesus D positive) will have Rh- (or rhesus D negative) blood.

      I hope that is helpful, but if it’s not, please feel free to reach out again.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  44. Jane

    Hello

    My father was O positive and both my sisters are too, I am AB rhesus negative, so what is mother?

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    • Hi Jane,

      Thanks for writing in.

      Blood types are comprised of two alleles. The most common (by far) are A, B, and O.
      — If a person has type A blood he or she has at least one A allele. He or she can have two A alleles (AA) but can also have one A and one O (AO). Both are called type A blood.
      — If a person has type B blood he or she has at least one B allele. He or she can have two B alleles (BB) but can also have one B and one O (BO). Both are called type B blood.
      — If a person has type O blood he or she has two O alleles (OO).
      — If a person has type AB blood he or she has one A allele and one B allele.

      Each person gets one allele from each parent, so IF you have AB blood type, you got an A allele from one parent (type A or AB) and one B alleles from the other parent (B or AB). A person with type AB blood can not have a parent with type O blood, because that person only has O alleles to pass down.

      Before you jump to any conclusions, it’s really wise to have all your blood types retested to be sure. For instance if you have type AB and your father has type B blood, your mother could be A or AB.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  45. Armia

    Is it possible for a child to have different blood type than his parents? My parents are both type O then my blood type is type AB+!

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    • Hi Armia,

      Is it possible for a child to have a different blood type than either of his or her parents, unless both parents have type O blood. Here’s the reason:

      Blood types are comprised of two alleles. The most common (by far) are A, B, and O.
      — If a person has type A blood he or she has at least one A allele. He or she can have two A alleles (AA) but can also have one A and one O (AO). Both are called type A blood.
      — If a person has type B blood he or she has at least one B allele. He or she can have two B alleles (BB) but can also have one B and one O (BO). Both are called type B blood.
      — If a person has type O blood he or she has two O alleles (OO).

      Each parent hands one allele down to his or her child. In the case of type O blood, the parent can only hand down an O allele. If both parents have type O blood, each can only hand down an O allele, so each of their children will have type O blood.

      Having said all that, it’s not uncommon for blood types to be different than they are thought and it’s wise to have all your blood retested before jumping to any conclusions.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  46. Dino

    Hi, I am the father with blood type O- and both my children (Boy and Girl ) is AB + I have read that it is not possible.
    Thanx

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    • Dino,

      Thanks for writing in.

      Our current understanding of genetics is that it is not possible for one parent to have type O blood and his or her children to have type AB blood. For a child to have type AB blood one parent must provide an A allele and the other parent provide a B allele. People with type O blood only have O alleles.

      However, it’s not uncommon for blood types to be different than they are thought. It is wise to have all your blood retested before jumping to any conclusions.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  47. PRATYUSH SAHOO

    Hello.
    I’M PRATYUSH SAHOO.
    MY father is having O+ve blood and my mother is having B+ve blood.

    And I am having O-ve blood is these RH conditions possible.
    plz help…..

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    • Hello Pratyush,

      Thank you for writing in and I understand your concern.

      Yes, it is possible for both parents to have Rh+ blood and their child to have Rh- blood. In fact 6.25% of children with two Rh+ parents have Rh- blood.

      Please let me know if you’d like more details.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  48. Nicki

    Hi Dr Greene,

    My Mother is Rh Negative (A) and my Father is AB Negative. I am A Rh D Positive.
    Is it possible that my father is my biological father if both my parents are a negative and I am a positive?

    Many thanks

    Nicki

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    • Hi Nicki,

      Thanks for writing in.

      If both parents are Rh-, they can only have children that are Rh-. Rh+ designates the presence of D Antigen. Rh- designates the absence of D Antigen. If it is not there, it can not be passed down. However, it’s not uncommon for blood types to be different than they are thought. The best next step is to have all three of your blood types retested.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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      • Nicki

        Many thanks Ms Greene,
        Some more information has come to light, unfortunately further proving that my Father is not my biological Father. He’s still my Dad though so that’s fine by me. Thanks again for your assistance.

        Kind regards,
        Nicki

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  49. sandeep

    i am O+ and my wife is A+ can my daughter be B+?

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    • Hello Sandeep,

      Thanks for writing in.

      Our current understanding of genetics is that it is not possible for one parent to have A+ blood, the other parent to have O+ blood and their child to have B+ blood.

      It’s not, however, uncommon for blood types to be different than they are thought. It is wise to have all your blood re-tested as a next step.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  50. Abbygale from Philippines

    Hi I’m Abbygale, I had my blood type test and it was resulted in Blood Type A+. My father and my mother was both blood type O. Is that really possible? Additional, some people believe that if you are the first child of your parent, you should have a same blood with your father. Specially if your a girl. Is that true? And is that possible that both Blood Type O parent can have a Blood Type A+ child? Thank you.

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    • Hi Abbygale,

      Thanks for writing in.

      It is not true that the first child should have the same blood type as the father — whether you are a male or female.

      Blood types are comprised of genetic material from the mother and the father. If both parents have type O blood, they can only pass down O, which means all their children will have type O blood. If one parent has type A blood and the other has type O, each of their children can be type A or O.

      It’s not uncommon for one parent’s blood type to be different than thought. It is wise to have all your blood re-tested before jumping to any conclusions.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  51. MJ

    Hi I am O- and my husband is B+ and our son is O+ is this possible?

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    • Hi MJ,

      Thanks for writing in.

      Yes, it is possible for one parent to have type O- blood, the other parent to have type B+ blood and their child to have O+ blood. In fact, there is a 25% chance each child from this couple will have type O blood and a 75% chance each child will have Rh+ blood.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  52. Shelly

    I have a question……I am RH O-. I have had 4 children and about 2 years ago was told that I have Trolli (not sure of the spelling) and that I can’t donate blood any more. Can you please explain what this is and how I got it?

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  53. Claire

    Hi,
    my sister is 0+, her boyfriend is 0-, and their son is A+.
    She told me in private she didn’t have sex with anyone else apart from the father of her son.
    Is there any possible explanation to this?
    Thank you for any help.

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  54. Glo

    Hello Dr. Greene,
    My Mother and Father both have O- blood. I have O+ blood. Is that possible?

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    • Hello Glo,

      Thanks for writing in.

      Our current understanding of genetics is that it is not possible for both parents to have O- blood and a child their child to have O+ blood. If one parent had O+ blood, and the other had O- blood, it would be possible for their child to have O+ blood.

      It is wise to have all your blood retested. It’s not uncommon for blood types to be different than they are thought.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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    • Ucheime

      Add your message here can parents with O+blood group donate blood to their children with O- negative blood group

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      • Ucheime,

        Thanks for writing in.

        In general, a person with blood type O- can only receive O- blood.

        If there is a question about your child needing a blood transfusion, your physician or local hospital can guide you in your specific situation. They will likely retest the family to confirm blood types.

        I hope this is helpful,
        Best, @MsGreene
        Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  55. RPXS

    Hi,

    My Mother is RH -A
    My Father is RH -O
    My oldest brother is RH -A
    My midle brother is RH -O
    And…
    …I’m the youngest (and I must be the bIack sheep in family) because I’m RH +O.

    I’ve already search that isn’t possible parents with (RH -A) and (RH -O) to have (RH +) positive childrens, can I be a rarely mutation? Or that’s not even possible?

    ps: Im pretty sure they are my parents, because me and my brothers have physical common traces from father and mother.

    Thanks in advance :)
    RPXS

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  56. Neelu

    When both father and mother has same blood group o positive then they will only conceive famale childs. Why do this happen? I have seen in many cases or every cases I have come across.

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    • Sometimes when someone flips a coin a few times it comes up the same every time – but with enough results, you’ll see both results. Some families do have all girl children. Some have all boys. But if you know enough different families with two O+ parents, you’ll see. They can have either girls or boys. Best, DrGreene

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  57. maryann

    i am o postive both of my daughters are rh negative what blood type is the father for them to be rh negative

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    • Hi Maryann,

      Thanks for writing in.

      If one parent is Rh+ and the other is Rh-, their children can be either Rh+ or Rh-. Even if both parents are Rh+, their children can be Rh+ or Rh-. That means, if you are Rh+ and if your children are Rh-, their father could be Rh+ or Rh-.

      If you’d like an explanation of how that works, let me know.

      I hope that’s helpful,
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  58. Kara

    Hello Dr,
    Recently I learned that both my mother and father have an O+ blood type and both of my sisters have O+ as well. I am the only child who has B+, my dad is also not listed on my birth certificate and I have a different last name from my mother and father, it is a possibility that I am not related to my mother or father?

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    • Hi Kara,

      Thanks for writing in.

      If both parents are O+ their children can be O+ or O-, but not B+. It’s always wise to have blood types re-checked as they are not always what people think they are, either because there was a mixup somewhere along the line or they are remembered incorrectly.

      It sounds like you need to ask your parents about your last name and birth certificate. I would guess that they are anticipating this conversation and just waiting for you to ask.

      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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      • Kara

        Ms. Greene,
        Thank you for responding back and giving me some more clear answers. Seems as though there are a lot of questions I need answers too.

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  59. sanu

    My wife blood ab posative my blood group o negative but baby b posative why

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    • Sanu,

      Thanks for writing in.

      If one parent is AB+ and the other is O-, it is perfectly normal for their child to be B+. The child would get a B allele and positive antigen from the AB+ parent and an O allele and negative antigen from the other parent, but that is called B+.

      Let me know if you’d like more explanation.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  60. Debbie

    If my Mother is AB- and my Father is O+ how can I be AB-. Wouldn’t this mean that my Father is not my real Father? I have the RH factor and I think my Mother did 2. She is no longer alive and my Father will do not do testing so I think he knows he I may not be his. Sad!

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    • Hi Debbie,

      I’m so sorry to hear of your upsetting situation.

      For a child to be AB-, she has to get an A from one parent and a B from the other. A person with type O blood can not hand down either an A or a B. A child can have Rh- blood even if one or both parents are Rh+, so that is not an issue in your situation.

      Often blood types are not what they are thought to be, so there is a chance that all three blood types do fit together. Since your mother is no longer living, she can not be tested. Since your father is unwilling to be tested, he can not be tested. But you could consider checking on your blood type. If you were type A or B, you could have a mother who is AB and a father who is type O.

      Sorry I couldn’t be more helpful.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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      • Ayla G.

        How about if the father with O type is A Bombay blood type,
        I think it is possible, If the father with blood type has A or B without antigens, test shows him as O blood type, but in reality He might be A or B in his genes.

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  61. tricia

    I am AB+ (confirmed by reliable sources), my mother is A+(confirmed as well) , and my father is O+ (Confirmed). Is this possible?

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  62. Butler Carolyn

    I have Rh A negative blood.
    Both my parents have o positive.
    Or so I have been told. I have breast cancer and before anything happens I would love to get answers. Is this my father? He has passed now and I am older but need closure.

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    • Carolyn,

      I’m so sorry you have breast cancer. I had metastatic, triple negative, inflammatory breast cancer 21 years ago. That’s an aggressive cancer, but I’m here today, which I hope is an encouragement to others.

      You are correct that two O+ parents can not have a child who is A-. You are in a tough position. Since your father has passed away, you can not confirm his blood type. Sadly, blood types are often different than people think they are. This can happen because there was a lab error, a reporting error or inaccurate memory.

      So for instance, if both parents are O+, they could have a child that’s O+ or O-. Or if one parent was A+ and the other was O+, they could have a child who is O+, O-, A+ or A-.

      If your father was still living there are inexpensive DNA tests that are 99.99% accurate. If this is terrible important to you and you have some samples of his DNA (root of a hair for instance) there are expensive ways to have DNA tests run, but I’m afraid I don’t have information about them.

      I wish I could offer you the closure you’re looking for, but I’m afraid I can not.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  63. Vijaya

    we both are O positive blood group but I dont understand how come my baby blood group is AB positive.
    Please advise me is this possible?

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  64. Lea

    My father is B+ and my Mum is O and my brother and sister have B+. And I am having an O blood type, is this possible?

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    • HI Lea,

      Thanks for writing in.

      Yes, it is possible for one parent to have B+ blood, the other to have O blood, and to have one child who has B+ blood and another who has O blood type. If you’d like an explanation, please let me know.

      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  65. Heathee

    Hi I’m 39 an have a daughter that is 23 an I am RH- an so is she.. I was wondering what blood type would her father most likely be for her to end up with my blood type an if a paternity yes would show negative on him due to my blood type

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  66. David

    My blood type is AB- and my sons mother is O-. Both of us have had our blood type tested many times. My son is B+. Is this a normal occurance?

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  67. jane

    Hi. I have AB Blood, my sisters all have O,, I had my mother health records yrs. ago but lost them but I am sure she was an O.. where did I COME FROM…WAS SHE MY MOTHER ???

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    • Hi Jane,

      Thanks for writing in.

      Unfortunately, you may never know for sure, but I can tell you there are several combinations of parents’ blood types that can result in their child having type AB blood. The only blood type that can not have an AB child is type O.

      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  68. Arthur King

    Hi, My blood type is O+, my child mother blood type is O+, is it possible for the child to have an A+ blood type?? Kindly provide an urgent response.

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    • Dear Author,

      Thanks for writing in.

      Our current understanding of genetics is that it is not possible for two parents with O+ blood to have a child with A+ blood.

      It is wise to have all your blood re-tested. It’s not uncommon for blood types to be different than they are thought.

      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  69. Kathy

    Hi, I’m wondering why I have blood type ‘O’, despite my mother having blood type ‘O’ and my dad having blood type ‘AB’. Isn’t this impossible?

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    • Hi Kathy,

      Thanks for writing in.

      Typically this would indicate that either the blood types are not what you think they are (i.e. you are not type O or your father is not type AB) or the man you call father is not your biological father. There is however a very rare blood type (0.0004% or about 4 per million in the general population) known as the Bombay Blood type. In some places such as Mumbai (which was formerly called Bombay) the occurrences can be as high as 0.01% or 1 in 10,000. This group does not fall into the ABO system and the usual tests for ABO blood show them as group O.

      The Bombay blood type is usually only found in small communities where there are other people with the hh blood type. Both parents have to be h carriers, though a parent can be a carrier without actually having Bombay type blood.

      If you suspect you may have the Bombay blood type talk to your doctor about a specialized test for this blood type as it does not show up using the normal ABO blood type tests.

      DNA paternity tests are still accurate (99.999%) with type hh blood and are considered the only accurate test for paternity.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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      • Kathy

        Thank you very much for replying, Ms Greene. Well, I asked both of my parents whether they are sure their blood types are correct and they were positive. I’m still not convinced, though, as they might be wrong too! There could be a misdiagnosis while deciding their blood types.

        I have another question though, is it possible for a person with blood type O to have a child with a person with blood type AB? What will happen their child?

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        • Hi Kathy,

          There are no special problems related to blood types if one parent is type O and the other parent is type AB, unless the mother is Rh- and the father is Rh+. For more information on that, you can read Dr. Greene’s article How To Determine and Manage Rh Incompatibility.

          Also, it is very common for blood types to be different than people think they are. It’s really worth getting retested if there’s any question.

          Best, @MsGreene
          Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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          • Varun

            Both parents has 0+ blood group and baby has A+. Is this normal? Or father is not biological father?

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          • Hi Varun,

            Thanks for writing in.

            According to our current understanding of science, if both parents have O+ blood, their children can only be O+ or O-.

            It is wise to have all your blood retested. It’s not uncommon for blood types to be different than they are thought.

            I hope that helps.
            Best, @MsGreene
            Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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        • Jasmine

          i have a question me and my brother both have o- blood and so does my mom but my dad has ab blood and i was just told by my health teacher that was impossible for that to happen…..and i look like my dads mini me basically…..am i being told my dad isnt really my dad?

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          • Hi Jasmine,

            Thanks so much for writing in.

            Our current understanding of genetics is that it is not possible for both parents to have type O blood and their child to have AB blood. An AB parent can only have children who are A, B or AB.

            However, it’s not uncommon for blood types to be different than they are thought so it’s is wise to have all your blood retested.

            If there is still a question, a DNA paternity test is the only test considered definitive. They are considered 99.999% accurate.

            I hope that helps.
            Best, @MsGreene
            Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  70. Christina

    I have long wondered if I may be adopted. My mother was A+ and my father was B+. I am AB-. What little I know about genetics suggests that either one or both of my parents (they were truly lovely people) was not my biological parent.

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    • Hi Christina,

      Thanks for writing in.

      As it turns out, if one parent is A+ and if the other is B+, it is completely normal for their child to be AB-. If you’d like an explanation, please let me know.

      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  71. J

    hello , i have a question. if i am A+ and my partner is B+ is it possible that my antibody screening can come back positive for pregnancy?

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  72. Shade trapiana

    Hi mother is o+ and dad is A+. The baby is A- what are the odds of that.

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    • Hi Shade,

      Thanks for writing in.

      If one parent has O+ blood and if the other has A+ blood, the chance that each of their children has type A blood is 75%. The chance that each of their children is Rh- is 6.25%.

      I hope that’s helpful,
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  73. Ceyana Briggs

    Hi I am O positive and my husband is B negative. Is it possible to have a baby with O positive blood type?

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    • Ceyana,

      Thanks for writing in.

      Yes, it is possible for one parent to be O+, the other parent to be B- and their child to be O+. If you’d like an explanation, please let me know.

      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene.

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  74. MWJ

    If one parents are O Negative the other the O positive can you get a baby born with a B blood type

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    • Hi MWJ,

      Thanks for writing in.

      Our current understanding of genetics, is if both parents have type O blood, their children can ONLY have type O blood.

      It is so common for people to think they have one blood type and actually have a different one, that doctors always check for blood type before they give someone blood. It is wise to have all three types retested before jumping to any conclusions.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  75. May.H

    My mom is AB positive, my dad is 0 negative, I’m 0 negative,my brother is 0 negative, my sister is O positive, does that mean our sister is not from one of our biological parents? We all have had childern and our blood has been tested because of the RH factor negative. Being O negative. Thank you, I hope you can help both my brother and I we have wondered about this for manys years and have not said anything to our sister. Your Sincerely

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    • Hi May,

      Thanks for writing in.

      Has your mom’s blood type been confirmed as AB+? I ask because, according to our current understanding of science, a parent with AB blood can not have a child with type O blood.

      On the other hand:
      — If one parent is Rh+ and the other is Rh-, they can have children who are Rh+ or Rh-.
      — If both parents are Rh+, they can have children who are Rh+ or Rh-.
      — If both parents are Rh-, they can only have children who are Rh-. They can not have children who are Rh+.

      I hope that’s helpful.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  76. J King

    One parent the mother is At and the alleged father is A-. What blood type will the baby be?

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    • Hi J,

      Thanks for writing in.

      If one parent is A+ and if the other parent is A-, each of their children could be A+, A-, O+ or O-.

      Please let me know if you’d like an explanation.

      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  77. Kaiti

    My mom is A positive, my dad is B positive, but I’m 0 negative, does that mean one (or both) are not my biological parents?

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    • Hi Kaiti,

      Thanks for writing in.

      Blood types are comprised of two alleles. The most common (by far) are A, B, and O.
      — If a person has type A blood he or she has at least one A allele. He or she can have two A alleles (AA) but can also have one A and one O (AO). Both are called type A blood.
      — If a person has type B+ blood he or she has at least one B allele. He or she can have two B alleles (BB) but can also have one B and one O (BO). Both are called type B blood.

      Rh+ means a person is positive for the D antigen. Rh- means a person does not have the D antigen.
      — If a person is Rh+, he or she can have a child that is Rh+ or Rh-.
      — If a person is Rh-, he or she can only have a child that is Rh+ if the other parent is Rh+.
      — Two parents with Rh- blood can not have a child with Rh+ blood.
      — Two parents with Rh+ blood can have children with Rh+ or Rh- blood.

      What all this means is if your mom is A+ and if your dad is B+ they could have a child who is O- and that would be perfectly normal.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  78. Robin

    I am O+, my husband A+. My oldest is A+ and youngest daughter A-. This is possible correct? My youngest daughter is worried cause she is A-. We have a son, as well, but his blood type unknown.

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    • Hi Robin,

      Thanks for writing in.

      If one parent is O+ and if the other parent is A+, there is a 75% chance each of their children will have type A blood and a 6.25% chance each of their children will be Rh-.

      If you’d like an explanation, let me know.

      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  79. Cecilia

    Hi! I have been thinking for some time if I am really be my parent’s daughter. I could have been switched at birth. My mother and father have AB+ blood and O blood type respectively. I got O+ type, could they not really my biological parents?

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    • Cecilia,

      Thanks for writing in.

      Our current understanding of genetics is that it is not possible for one parent to be AB+, the other parent to be O and their child to be O+. An AB parent can only have children who are A, B or AB (depending on the blood type of the other parent).

      It is wise to have all your blood retested. It’s not uncommon for blood types to be different than they are thought.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  80. dancerdancer42

    Hi. I have the rarest blood type, AB-. My mom has A+, and my dad has O+. I personally think I could’ve been switched at birth. My mom denies it every time I ask her/when I try to tell her that it’s possible. I found out my dads and my moms by saying that I needed to know their blood types because of a school project. I know lying is wrong, but when my mom refuses to think that it could be possible, she hears what she wants. My dad and my sister believe that it could be possible. When I brought it up at the dinner table once, my dad told me that when I was born, the doctors couldn’t give me back to my mom right away because of a mix up with the bracelets that we were wearing. Seems a little weird. Is there anyway that I could be my parents daughter, despite the blood type differences?

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    • Dear Dancer,

      Thanks for writing in.

      Our current understanding of genetics is that it is not possible for one parent to be A+, the other parent to be O+ and their child to be AB-. That said, it’s not uncommon for blood types to be different than they are thought. It is wise to have all your blood retested before jumping to any conclusions.

      If there is a question, a DNA paternity test is the only test considered definitive to establish paternity or maternity. The tests are fairly inexpensive, can be ordered online, taken in the privacy of your own home, mailed in, and results received by mail. They are considered 99.999% accurate.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  81. Sandy

    Hi
    Father is A+ Mother negative first 3 children are A+ child 4 RH-2 So is father the father of #4? And has anyone made a connection with RH- children not getting the normal childhood diseases. Like chicken pox, missals, ect. Thank you

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    • Hi Sandy,

      Thanks for writing in.

      If one parent is A+ and if the other parent is A-, each of their children could be A+, A-, O+ or O-. Does that answer your question?

      I am unfamiliar with a link between Rh- blood and extra immunity to normal childhood diseases.

      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  82. brenda owens

    hi I have a positive blood my mom is rh negative my dad a positive its been said my dad cannot be my bio father is this blood type not possible

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    • Hi Brenda,

      Thanks for writing in.

      If one parent has Rh- blood and the other has Rh+ blood, each of their children can be Rh+ or Rh-.

      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  83. Tia

    Hi, I have a question, my blood group is A+, my mum is O-, and my dad is B-, is it possible my dad may not be my dad.

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    • Hi Tia,
      Thanks so much for writing in! Our current understanding of genetics is that it is not possible for one parent to be B-, the other parent to be O- and their child to be A+. An B parent can only have children who are B or O.

      It is wise to have all your blood retested. It’s not uncommon for blood types to be different than they are thought.

      I hope that helps.
      Alexandra (caring helper at DrGreene.com, not a doctor)

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  84. Sarah

    I have a question; my mom has A Positive blood and my dad has B Positive blood. My older brother and I both have AB Negative blood. What are the chances of such an occurrence?

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    • Hi Sarah,

      Thanks for writing in.

      If one of your parents is A+ and the other is B+, there is a 56.25% chance each of their children will be AB and a 6.25% chance each child will be Rh-. The odds are the same for each child, so the fact that you are both the same are not unexpected, but still very cool.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  85. Akib

    Can O father have a child AB…I am not sure about mother…Is there any chances of AB child…any mutation effects or its impossible

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    • Akib,

      Thanks for writing in.

      Our current understanding of genetics is that it is not possible for one parent to be O, and their child to be AB.

      It is wise to have both your blood retested. It’s not uncommon for blood types to be different than they are thought.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  86. G SARAN

    IN IVF MY BLOOD IS A POSITIVE AND MY HUSBAND BLOOD IS O POSITIVE HOW MY BABY AB NEGATIVE

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    • Thanks for writing in.

      The testing during IVF if extensive. I’m not a physician, but if this were me, I’d ask the IVF doctor to explain. He or she may want to retest to confirm all blood types.

      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  87. Ali

    My Blood group is O+ and my wife has B+ but son has A+ , what does it means

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    • Ali,

      Thanks for writing in.

      Our current understanding of genetics is that it is not possible for one parent to be O+, the other parent to be B+ and their child to be A+. If one parent is B+ and the other parent is A+, A-, AB+ or AB-, it would be possible to have a child who is A+.

      It is wise to have all your blood retested. It’s not uncommon for blood types to be different than they are thought.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  88. Michaela

    Both my parents have O positive and while I have AB positive

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    • Hi Michaela,

      Thanks for writing in.

      Our current understanding of genetics is that it is not possible for both parents to be O+ and their child to be AB+. Two O+ parents can only have children who are O+ or O-.

      It is wise to have all your blood retested. It’s not uncommon for blood types to be different than they are thought.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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      • geetha

        Father O+ mother b+ but child AB+ is possible

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  89. Trina

    Baby is O+ . Father is O- and I am B- is that possible

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    • Hi Trina,

      Thanks for writing in.

      Our current understanding of genetics is that it is not possible for both parents to be Rh- and and their child to be Rh+. It is possible for one parent to be type O, the other to be type B and their child to be type O.

      It is wise to have all your blood retested. It’s not uncommon for blood types to be different than they are thought.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  90. SAHIL SHARMA

    HELLO,
    MYSELF SAHIL. I HAVE 4 KIDS.MY BLOOD GROUP IS A+ AND MY WIFE BLOOD GROUP IS A+.
    TWO OF OUR KIDS BLOOD GROUP ONE IS B+ AND ANOTHER IS AB+ .
    AS PER ABOVE CAN YOU PLEASE HELP ME KNOW THAT IS IT POSSIBLE.

    REGARDS

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    • Dear Sahil,

      Thanks for writing in.

      Our current understanding of genetics is that it is not possible for both parents to be A+ and their child to be B+ or AB+. If two parents are A+ each of their children can be A+, A-, O+ or O-.

      However if one parent is A and the other is B or AB, and if at least one or both of the parents have Rh+ blood, they could have children who are A+, B+ or AB+.

      It is wise to have all your blood retested. It’s not uncommon for blood types to be different than they are thought.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  91. Tosbrawn

    hello Dr Greene.

    pls am B Rh D positive and my wife is B Rh D negetive but my son is O Rh D positive could that be possible.

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    • Toshbrawn,

      Thanks for writing in,

      Yes, it is possible for one parent to be B Rh D positive and the other to be B Rh D negative and their child to be O Rh D positive.

      When the mother is positive and the baby is negative, their can be incompatibility issues and the mother needs treatment before having any additional children. Has your wife had treatment?

      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  92. Molly

    Hi, my blood type is O+, my fiancé blood type is O+ and my son’s blood type is O+. What are the probabilities of my fiancé being the father to my son in terms of percentage. Thanks

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  93. rajib das

    sir i am A + and my wife is A- but our baby is O+ is it possible
    or other way i.e my wife is sex with other person who is O+

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    • Rajib,

      Thanks for writing in.

      It is completely normal for one parent to be A+, the other to be A- and their child to be O+.

      Blood types are comprised of two alleles. The most common (by far) are A, B, and O. Each person also has the presence of D antigen (which we call Rh+) or the absence of D antigen (which we call Rh-).

      — If a person has type A blood, he or she has at least one A allele (this can be AA or AO).

      — If a person has type O blood, he or she has two O alleles (OO).

      This means if your blood type is A+ and the mother of your baby’s blood type is A-, each of you would have passed an O allele down to your child.

      Additionally, if your wife is A- and if you are A+, the Rh+ would have come from you and could not have come from her. This leads to a much bigger issue and one I’m sure your doctor has addressed. The two of you have blood type incompatibility and she must be treated before you have a second child. If this has not been addressed, bring it up with her physician immediately.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  94. Cara

    Hi! I was just wondering. I am O-/RH- and my husband is O+. We have two children, a boy and a girl. Would it be more likely for them to have RH- since I have it? (Sounds odd saying I have something that technically says negative, as in none- lol)
    I know my father wasn’t RH- but my mother was.

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    • Hi Cara,

      Thanks for writing in.

      If one parent is O- and the other is O+ there is only a 6.25% chance that each of their children will be Rh- and a 93.75% chance each child will be Rh+. There is a 100% chance each will child will have type O blood.

      It doesn’t matter which parent has Rh+ and which parent has Rh- blood.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  95. Yna

    My husband is type O+and me is type B+ it is possible to get a baby type A+

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    • Yna,

      Thanks for writing in.

      Our current understanding of genetics is that it is not possible for one parent to be B+, the other parent to be O+ and their child to be A+. These two parents could only have children that are B+, B-, O+ or O-.

      It is wise to have all your blood re-tested. It’s not uncommon for blood types to be different than they are thought.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  96. Jenny

    Great stuff above, Question: from my 30 year old daughter, supposedly two parents who are O negative have an A negative baby (30 year old ) is this a mutation ? She is the first the others are all O negative ?

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    • Hi Jenny,

      Thanks for writing in.

      If both parents are O-, their children can only be O-.

      My guess is either one of the three blood types isn’t what people think it is or there is a different father for the first child. DNA paternity tests are 99.999% accurate.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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    • geetha

      B+&O+ to be matching AB+ is possible to match

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      • Geetha,

        Thanks for writing in.

        Our current understanding of genetics is that it is not possible for one parent to be B+, the other parent to be O+ and their child to be AB+.

        It is wise to have all blood retested. It’s not uncommon for blood types to be different than they are thought.

        I hope that helps.
        Best, @MsGreene
        Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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      • maya

        Father O+ mother b+ child A1b+ is possible

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  97. georgina

    If my mum is B+ and my dad is A+ what am i?

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    • Hi Georgina,

      Thanks for writing in.

      If your mom is B+ and your dad is A+, you are in a unique situation. With those two types you could be any blood type. This is the only parental combination that can combine to make any blood type.

      If you’d like an explanation, please let me know.

      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  98. Shaaz

    Can a child have B+ blood group if both his/her parents are O+ ?

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    • Dear Shaaz,

      Thanks for writing in.

      Our current understanding of genetics is that it is not possible for two parents with O+ blood to have a child with B+ blood. Two parents with O+ blood can only have children with O+ or O- blood.

      It is wise to have all your blood retested. It’s not uncommon for blood types to be different than they are thought.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  99. natasha

    Hello,
    I would like to know what my dad’s blood would be as i am B+ and my mom think she is O, don’t know which one – or + so I would be appericate if could you give me an answer what possiblity and impoosible to have? as i know my sister is O- so i have more siblings as they dont know what their are.
    thank
    Natasha

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    • Hi Natasha,

      Thanks for writing in.

      If your mom has type O blood and you have and if you’re B+ and if your full sibling is O-, then your father could only be B+ or B-. We know this because you had to get at least one B allele and you could not get it from your mother. We know he could not be type AB because if he was, your full sibling could not be type O.

      If you are are Rh+ then one of your parents must be Rh+. Both can be Rh+ and your sister could still be Rh-, so that doesn’t help narrow down whether your father is Rh+ or Rh-.

      All of this assumes that you are correct in your blood type and the blood types of your mom and your sister.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  100. Luis

    Hi! If my wife is o+ and my 3 kids are o+,B+ and A+ ……. What would mine be?

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    • Hi Luis,

      Thanks for writing in .

      According to our best understanding of current science, if the mother of your children has type O+ blood, there is no blood type you could have that would allow you to have one child who is type O+, one that is type B+ and one that is type A+.

      If on the other hand, if one parent is type A and the other parent is type B, the two parents could have one child who is type O+, one that is type B+ and one that is type A+, if at least one of the two parents was Rh+.

      It is wise to have all your blood retested. It’s not uncommon for blood types to be different than they are thought.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  101. Nikhil

    If my parents have B+ and B- blood types, then is it possible for me to have AB+ blood type?

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    • Hi Nikhil,

      Thanks for writing in.

      Our current understanding of genetics is that it is not possible for one parent to be B-, the other parent to be B+ and their child to be AB+. Two B parents can only have children who are B or O. If one or both parents is Rh+ their children can be Rh+ or Rh-.

      It’s not uncommon for blood types to be different than they are thought. It is wise to have all your blood retested.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  102. Tracy

    Hi, I have a question please.
    My mother is type B+ and my father is type O+.
    Both my sister and I are AB+.
    The results are correct as we have all been tested several times.
    Are you able to say how this has occurred, and possibly give some explanations please?
    Thank you

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    • Tracy,

      That’s a great question.

      There is a very rare blood type (0.0004% or about 4 per million in the general population) known as the Bombay Blood type. In some places such as Mumbai (which was formerly called Bombay) the occurrences can be as high as 0.01% or 1 in 10,000. This group does not fall into the ABO system and the usual tests for ABO blood show them as group O even though they are hh. This could be your father’s type and could explain why the tests say he’s type O.

      If you suspect you father may have the Bombay blood type talk to your doctor about a specialized test for this blood type as it does not show up using the normal ABO blood type tests.

      DNA paternity tests are still accurate (99.999%) with type hh blood and are considered the only accurate test for paternity.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  103. Emelyn

    Hi i found out that my baby is +b blood type and im +O and im asking the father of my child he said he is sure that he is +O as well.
    Is it possible to have a +B baby with both parents are +O?
    My baby is sick with metabolic disorder,horshoe kidney,renal failure.
    Your answe will be a big help.
    Thank you

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    • Emelyn,

      I’m so sorry to hear that your child is so sick. That must be heart breaking.

      Our current understanding of genetics is that it is not possible for both parents to have O+ blood, and their child to have B+ blood. Two O+ parents can only have children who are O+ or O-.

      It is wise to have all your blood retested. It’s not uncommon for blood types to be different than they are thought.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  104. Florence

    Hi, my Mum was A+ and Dad was O+ is it possible that my blood is A-? Thanks!

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    • Hi Florence,

      Thanks for writing in.

      Yes, if your mum’s blood type was A+ and your dad’s blood type was O+, you could be A-.

      Let me know if you’d like an explanation.

      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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      • Sb

        Hi I’ve been trying to figure out my blood type for years. My daughters are B positive and O positive. My mom is A positive and my dad is O not sure positive or negative. I can’t donate blood due to small veins and my dr won’t do the test due to cost. My mom believes I’m O but doesn’t know positive or negative. Can you help?

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        • Sb,

          Thanks for writing in. It’s hard to determine blood types without tests, but here’s what we know.

          If your mom is A+ and if your dad is O + or O-, you could be A+, A-, O+ or O-.

          Your daughter would have gotten the B from her father. If your children’s father is Rh-, you are Rh+.

          That’s all we know for sure for the information you’ve provided.

          Best, @MsGreene
          Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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        • L. S.

          Sb, just so you know, most blood banks will test your blood type when you give at no cost to you. I can only go from my experience from the state in which I live and that my donations went through the Red Cross. If you truly want to give blood, I’d suggest that you check with the Red Cross where you live.

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  105. Paula

    I have 3 siblings one blood type O NEG and 2 A POS mine is A neg would we have the same parents?

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    • Hi Paula,

      Thanks for writing in.

      The short answer is yes, you could have the same parents. If one of your parents had type A blood and the other had A, O or B and one or both of your parents were Rh+, you could all be full siblings.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  106. Jordyn Miller

    My mother has A+ blood and my father has O- blood. How is it possible for me to be AB+?

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    • Hi Jordyn,

      Thanks for writing in.

      Our current understanding of genetics is that it is not possible for one parent to be A+, the other parent to be O- and their child to be AB+. A parent with type O blood can not have a child that is type AB.

      It is wise to have all your blood retested. It’s not uncommon for blood types to be different than they are thought.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  107. Sruthi

    Am B negative , my mother is O positive & Dad is B positive how can I be B negative?

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  108. Ronald Chriscoe

    If my mother an father are A+ is it possible to make a O+ baby?

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    • Hi Ronald,
      Thanks for writing in! Our current understanding of genetics is that it is not possible for both parents to be A and their child to be O. It is wise to have all your blood retested. It’s not uncommon for blood types to be different than they are thought.
      Hope that helps!
      Alexandra (caring helper at drgreene.com, not a doctor)

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    • Dr.Safia

      Yes. It is possible for parents who are AO (i.e. A+ or A-) and AO (A+) to have kids that are either AA (A+) , AO (A+) or OO (O+).

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  109. S crockett

    Out of all my siblings their all a and b blood why am I rh have to get a shot while pregnant

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  110. Lawanda Lindsey

    My parents are both o positive and my sister is A negative. I am Ab negative so how is that possible

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    • Hi Lawanda,
      Thanks so much for writing in! Our current understanding of genetics is that it is not possible for both parents to be O and the kids to be A and AB.

      It is wise to have all your blood retested. It’s not uncommon for blood types to be different than they are thought.
      Hope that helps!
      Alexandra (caring helper at drgreene.com, not a doctor)

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      • Marcia

        Hi, if both my parents are A+ why my blood type turned out to be A-.

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        • Hi Marcia,
          Both your parents could be carriers of Rh-, even though they show up as positive, so it’s possible they both passed the negative allele to you.
          Hope that helps!
          Alexandra (caring helper at drgreene.com, not a doctor)

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  111. Thomas Rendleman

    Is it possible for an O Neg and an AB+ to still have O Neg children. The AB+ doesn’t have RH Neg in family.

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  112. Swathi

    Hello Dr,
    What will be the blood group of the child of parents having blood group A+ and B-

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  113. Kayla

    Im A+ is it possible to have a parent o- and o+

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    • Hi Kayla,
      Thanks for writing in! Our current understanding of genetics is that it is not possible for one parent to be O-, the other parent to be O+ and their child to be A+. One parent would have to be A or AB to have an A child.

      It is wise to have all your blood retested. It’s not uncommon for blood types to be different than they are thought.
      Hope that helps!
      Alexandra (caring helper at drgreene.com, not a doctor)

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  114. Khalid

    Hello dr.

    I need your kindly help , I am (A+), and my wife is (AB+), and my daughter ( A-) !?
    1- Is it possible to have a child with (A-)blood , while I’m (A+) and my wife (AB+) ?
    And what is the possibility of the child blood groups with their RH -+ in our case ?

    Thanks in advance for your help and appreciate your soonest reply .

    Regards,

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  115. Lia

    Hi Dr. Greene,

    I was wondering about my blood type since it is different with my parents. My blood type is A+, while my father is O+ and my mother is B+. I was searching about this but couldn’t find the right answer yet.

    For your information, all of my father’s family’s blood type is O+, and my mother’s parents are O+ and B+. I have a younger sister which blood type is B+.

    Can you please explain why my blood type is different with them?

    Your answer will be very helpful to me. Thank you :)

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    • Hi Lia,
      Thanks so much for writing in! Our current understanding of genetics is that it is not possible for one parent to be O, the other parent to be B and their child to be A.

      It is wise to have all your blood retested. It’s not uncommon for blood types to be different than they are thought.
      Hope that helps!
      Alexandra (caring helper at drgreene.com, not a doctor)

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      • Mary

        I am O+ and my husband is A+. Is it possible to have a O- child?

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        • Yes, this is possible. You could both be carriers of the Rh- allele, and then it could be passed on to your child.
          Hope that helps!
          Alexandra (caring helper at drgreene.com, not a doctor)

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  116. Alex

    My father’s blood group is B+ and my mother’s blood group is O+
    …I have a elder brother with O+ blood type
    ….but I am AB+….I have read on many websites it is impossible for me to have AB+.Can someone please explain me how/why?

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    • Hi Alex,
      Thanks so much for writing in! Our current understanding of genetics is that it is not possible for one parent to be O, the other parent to be B and their child to be AB.

      It is wise to have all your blood retested. It’s not uncommon for blood types to be different than they are thought.
      Hope that helps!
      Alexandra (caring helper at drgreene.com, not a doctor)

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  117. Kate

    Both my husband and I are 0+, but one of our sons is AB-, which I have been told is rare.
    We weren’t told of his blood type at the time of birth, we found out later. I did have the Rhesus injection a day or so after his birth.
    I’ve been told that this is impossible. When I discussed it with our family doctor, he told me ‘not to go there’

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    • Kate,

      How tough. You are right, this doesn’t match our medical understanding, but there are a couple of issues.

      1) If you are Rh+ you do not need the Rhesus injection. A couple of options — either you are not the blood type you think you are, you got a different injection, or it was given to you in error.

      2) If both parents are O+ and if the baby is AB-, neither parent is the biological parent.

      Your options include having all blood re-tested, DNA paternity / maternity tests, and “not going there”.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  118. Mo

    Hi, my ex husband and I are both Rh B positive, my eldest daughter is Rh D negative, is this possible?

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    • Maureen

      My husband and I are both b.pls, my daughter is rh d negative, is this normal.

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      • Hi Maureen,

        Yes, it is normal for two parents with Rh+ blood to have a child with Rh- blood.

        If you’d like an explanation, please let me know.

        Best, @MsGreene
        Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

        Added:
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    • Hi Mo,
      Thanks so much for writing in! If your question is whether two Rh+ parents can have an Rh- child, the answer is yes if the parents are both Rh+- (there are two alleles, or forms, of the Rh gene that every person carries, and + is dominant, but if you both carry the – allele as well, it’s possible you could have both passed it on to her and she would present as Rh-).

      Hope that helps!
      Alexandra (caring helper at drgreene.com, not a doctor)

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  119. MJ

    Hi im 47 and resus neg blood both my parents are o positive iv been told one of them may not be my parent as this isnt possible ?? Im very confused pls help x

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  120. Therese

    Hi, my mother has A+ blood while my father has A- I also have A- blood, however, my brother has AB+ blood. My grandmother (mother’s side) has got AB+ blood if that makes a difference, all information about blood type inheritance I have come across says that A and A cannot =AB. Our blood types have been reconfirmed, do you think this is simply a mutation or that something else is to blame?

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    • Therese,

      Our current understanding of genetics is that it is not possible for one parent to be A-, the other parent to be A+ and a child their child to be AB+. Two A parents can only have children who are A or O.

      It is wise to have all your blood retested. It’s not uncommon for blood types to be different than they are thought. It sounds like you may have already retested. If so, consider a DNA paternity test. They are considered 99.999% accurate and will answer the question of mutation or “something else to blame”.

      Here’s a like to a simple home DNA test that can provide the information you are looking for while maintaining your privacy.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  121. Mary

    Hi,
    I am a mother with O+ & both my boys are O-. What would the father’s blood type have to be for this to occur?

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    • Mary,

      If your blood type is O+ and your son’s are O-, their father could be O+, O-, A+, A-, B+, B-, but could not be AB+ or AB-.

      If you’d like an explanation, please let me know.

      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  122. Lisa

    Hello,

    I am O+ and my boyfriend is O-
    We all retested our blood types and two totally different hospitals have indicated that our son is B+. He was with me from the day of his birth until the day of discharge. We even had matching security arm bands to prevent a mix up. My son is now five years old and I’m too scared to even think that he is not mine.
    Is his blood type possible?

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  123. Teena

    Hai doctor,
    I am Teena my age is 41 my blood group B+ve and my husband B-ve and my son O-ve if possible different blood group 3 of us?I heard about that its very complicated to get 2nd baby I want 1 more baby what i can do?please reply me?

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    • Hi Teena,

      If your blood type is B+ and your son’s father’s type group is B-, your son’s blood type can be O-.

      If the mother’s blood is Rh- and the father’s is Rh+, there can be difficulties with subsequent pregnancies. There is no issue if the mother is Rh+ and the father is Rh-.

      If you’d like further explanation, please let me know.

      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  124. AMSIS

    my mother is B+, my father is A+, I am B+, and two of my brothers are AB+ and A+ respectively. However, one of my brothers is O- and also has green eyes when we all have blue eyes. Is his blood group possible with the family blood grouping

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    • Amsis,

      Yes, if your mother is B+ and your father is A+, your siblings can be O-, AB+, A+ and B+.

      If you’d like an explanation, please let me know.

      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  125. shalini

    Hello dr.green,
    My husband and I are B +. We have our elder daughter with B- and younger daughter with O-. Is there anything that I should be concerned about in future? Can you please explain on this.

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  126. Divyanshi kapoor

    My father is B+ and my mother is O+. I am B-. Is this normal?

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    • Divyanshi,

      Yes, this is perfectly normal. If you’d like an explanation, please let me know.

      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  127. Mary

    Can an o- parent and a o+ parent have a child with rh blood?

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  128. Billy

    If the father is Type O+ and the mother RH- can the baby be A type

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    • Billy

      If the father is Type O + and the mother is RH- can the baby be A

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  129. Debra Gaynor

    My mother is O- and my father is A+ but my blood type is B+. I have been tested more than once and so has my mother plus my dad has donated blood more than once and was tested by the Red Cross. Can a mother with O- and a father with A+ have a child with B+?

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  130. biswajit

    I am b positive and my wife is o positive. My daughter has o negative blood group. Is it possible?

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    • Biswajit,

      Yes, it is possible for the father to have B+ blood, the mother to have O+ blood and their child to have O- blood.

      If you would like an explanation, please let me know.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  131. Misty

    My mom had O- and my dad had B+. I have A+. Is this possible? My younger sister was born Rh- and got a complete blood transfusion. No other siblings. I look like my mom.

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    • Misty,

      If your mother is O- and you are A+, your father is A+ or AB+.

      It is wise to have all your blood retested. It’s not uncommon for blood types to be different than they are thought.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

      Added:
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  132. Liss

    I am ab-. my mom is ab+ and her sister (my aunt) is o-. Can this be possible having the same parents?

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    • Hi Liss,

      If your grandparents were type A and type B and at least one of them was Rh+, they could have children who are AB+ and O-. There are no other combinations that would work, but that’s a fairly common combination (though I can’t tell you how common — sorry).

      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  133. Sherry

    Hi I’m O+ with a D factor I don’t know what that means my mom is AB/RH- my dad is A +
    When I was told as a child I was A+ with the D Factor but @ 18 I found out I was O+ with the D Factor.
    is it possible for me to Be this with my parents having these blood type?

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  134. Michelle

    I am RH B- and my daughter is A- and her father is O+. Is that possible

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    • Michelle,

      If the mother is B- and the child is A-, the father must be AB+, AB-, A+ or A-. He can not be O+, O-, B+ or B-.

      Blood types are often different than thought. The next step would be to re-test all three blood types.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

      Added:
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  135. Linda

    Can A+ mom and O- father have O+ child?

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    • Hi Linda,

      Yes, an A+ mother and an O- father can have an O+ child.

      If you’d like an explanation, please let me know.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

      Added:
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  136. Aimee

    Hello,
    I haven’t had a chance to scan through all these yet to see if this question has already come up but I just realized that my mother is O Rh- and I am AB Rh-. (My father can’t recall what type he is.)

    Could you explain this scenario a bit. This seems a bit unusual?

    Many thanks,
    Regards,
    Aimee

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    • Aimee

      Oh, I should maybe add that my mother has previously had O- transfusion without incident.

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    • Aimee,

      I can not explain this. If you are AB- you had to get an A from one parent and B from the other and an Rh- from each of them.

      Perhaps it’s time for everyone to be retested?

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  137. Christina

    If mother is rh- negative and baby is Rh-positive , what is Father?

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  138. Vanessa Martins

    Hi, my husband and I are both O+ but our daughter has A- blood. My mother has A- blood also. I don’t need to do a paternity test because my daughter looks EXACTLY like my husband. Is it possible she has A- from my mother? It’s a little concerning to us.

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    • Vanessa,

      This is not a combination that is considered possible. The most likely explanation is one of the blood types is different than you think it is. You may want to have all your blood retested.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

      Added:
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    • Mel

      I’m not a doctor but I’m on the same boat. Both my parents are both O+ and all my siblings are all O blood type. However on the other hand, I’m the odd daughter with the B+ blood type. All my family donated blood several times, so obviously they can’t be retested or questioned for their blood type. But as for me, I’ve gotten my blood tested several times lately and sure enough I’m still B+. For some reason I thought I read somewhere that it is possible that a baby can inherit their parents’ parents or from an uncle or aunt. I have no doubt that my dad is my dad. I look exactly my dad from skin, hair, feature and personality. I think it is possible to inherit any of the parents’ closed blood type relative.

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  139. James

    Me and my wife just welcomed our new baby boy to the world. We are both O positive and the baby is B negative. We are confused on how it is possible. Any help would be appreciated.

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    • Hi James,

      Congratulations!

      In a case like yours, it’s often wise to have all blood types retested. As you’ve already figured out, that’s not an outcome that is considered possible.

      If you are still concerned after retesting all three of your blood types, a DNA paternity test is the only test considered definitive. They are fairly inexpensive, can be ordered online, taken in the privacy of your own home, mailed in, and results received by mail. They are considered 99.999% accurate. Here is an example of one such test.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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      • Sarika

        Hey…..I am A+my husband is B+my daughter is ab-and my son o+ what do u think about this scenario ? How rare is it?

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        • Sarika,

          If you are A+ and the father of your children is B+, there is a 56.25% chance each child will be AB and a 6.25% each child will have type O blood. There is a 93.75% chance each child will be Rh+ and a 6.25% chance that each child will be Rh-. It’s all very interesting, right?

          Best, @MsGreene
          Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

          Added:
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  140. Tina

    If child is Rh- is it possible to have parents that are(father) b and (Mother)a?

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    • Tina,

      It is possible for a child to be Rh- if his or her parents have type B and type A blood.

      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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      • Tina

        My baby is Rh O+ does that mean she has rh factor?

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  141. Husna

    If my father is A+ and mother is B+, what am I?

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    • Husna,

      If your father is A+ and if your mother is B+, you could be AB+, AB-, A+, A-, B+, B-, O+ or O-. As you’ve probably figured out, this combination of parents is the only combination that doesn’t rule out any possible blood type in the child.

      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  142. courtney

    I am o positive. The father of my child is b negative. My son is a positive. Is that possible?

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    • Courtney,

      If one parent is Rh+ and the other is Rh-, each of their children can be Rh+ or Rh-.

      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  143. Joyce

    My mom told me when I was younger I was a+. So I told the doctors I’m a+ even the obgyn.. I didn’t find out till my 4th child I was o+.. my half siblings and my full blood brother r a+ like my dad and my mom is a- is there a possibility that my dad is my dad I don’t look anything like him but my sister and brothers do.. and my mom side of the family told me when I was 28 that my dad isn’t my dad.. and that I look like the other guy my mom was with when she was 16

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    • Joyce,

      If your mother is A+ and if your father is A+ you could be A+, A-, O+ or O-.

      Only a DNA paternity test can actually tell you if the man who raised you is your biological father, but these blood types don’t bring his paternity into question.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

      Added:
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  144. Ann

    my father is a B and my mother is a RH and I am an O how does that make any sense

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    • Ann,

      Blood types are comprised of two alleles. The most common (by far) are A, B, and O. We call blood types A, B, O and AB. but people with type A and B can also have an O allele. Here’s how that looks:

      1) If a person has type B blood he or she could have two B alleles (BB) or one B and one O allele (AO).
      2) If a person has type A blood, he or she could have two A alleles (AA) or one A and one O allele (AO).
      3) If a person has type O blood, he or she has two O alleles (OO).

      In the scenario you suggested, you could have received an O from each parent and you would then be type O.

      I hope that helps.
      Best, @MsGreene
      Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  145. Lyn

    If im a B+, my husband is AB, wht will be my child blood type?

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    • Lyn,

      If you’re B+ and the father is AB, your child could be AB+, AB-, B+ or B-, but not A+, A-, O+ or O-.

      If you’d like an explanation, please let me know.

      Best, @MsGreene
      Co-founder & Executive Producer, DrGreene.com
      Note: I answer a lot of questions on DrGreene.com, I am the co-founder of DrGreene.com, Dr. Greene’s business partner and wife, but I am a not doctor. Please keep that in mind when reading my comments and replies.

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  146. Ellen

    To have a child that is RH-, what type does the parents have to be.

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    • Ellen,

      If a child is Rh-, the parents can be either Rh- or Rh+.

      Let me know if you’d like an explanation.

      Best, @MsGreene
      Note: I answer a lot of questions on DrGreene.com, I am the co-founder of DrGreene.com, Dr. Greene’s business partner and wife, but I am a not doctor. Please keep that in mind when reading my comments and replies.

      Added:
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  147. Amanda

    If my mother is O+ and my father is AB+ what is my blood type?

    Added:
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    • Hi Amanda,

      If your mother is O+ and your father is AB+, you could be A+, A-, B+ or B-.

      If you’d like an explanation, please let me know.

      Best, @MsGreene
      Note: I answer a lot of questions on DrGreene.com, I am the co-founder of DrGreene.com, Dr. Greene’s business partner and wife, but I am not a doctor. Please keep that in mind when reading my comments and replies.

      Added:
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  148. Sarah

    If I am rh- and my child is rh- what must my ex husband be

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    • Sarah,

      He can be Rh- or Rh+.

      Let me know if you’d like an explanation.

      Best, @MsGreene
      Note: I answer a lot of questions on DrGreene.com, I am the co-founder of DrGreene.com, Dr. Greene’s business partner and wife, but I am a not doctor. Please keep that in mind when reading my comments and replies.

      Added:
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  149. Hazel

    If my mother was AB- and I am B+, what should my father be?

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    • Hazel,

      If your mother was AB- and you are B+, your father could be B+, AB+ or O+.

      Let me know if you’d like an explanation.

      Best, @MsGreene
      Note: I answer a lot of questions on DrGreene.com, I am the co-founder of DrGreene.com, Dr. Greene’s business partner and wife, but I am not Dr. Greene, nor am I a doctor. Please keep that in mind when reading my comments and replies.

      Added:
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      • Hazel

        Thank you.

        Thank you … what about an AB- mother with an A- child. What could the father be there?

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        • Hazel,

          If the mother is AB- and the child is A-, the father could be A+, A-, B+, B-, O+, O-, AB+ or AB-.

          Let me know if you’d like an explanation.

          Best, @MsGreene
          Co-founder & Executive Producer DrGreene.com, Mom
          Note: I answer a lot of questions on DrGreene.com, but I am not a doctor.

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  150. Rana singh

    Hi… My brother have A+ and his wife AB+ but their son is O+ how is it possible??? Please reply me

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    • Hi Rana,

      Typically we say that this is not possible — an AB mother can not have an AB child — however there is a very rare blood type (0.0004% or about 4 per million in the general population) known as the Bombay Blood type. In some places such as Mumbai (which was formerly called Bombay) the occurrences can be as high as 0.01% or 1 in 10,000. This group does not fall into the ABO system and the usual tests for ABO blood show them as group O.

      The Bombay blood type is usually only found in small communities where there are other people with the hh blood type. Both parents have to be h carriers, though a parent can be a carrier without actually having Bombay type blood.

      If you suspect a child may have the Bombay blood type talk to the child’s doctor about a specialized test for this blood type as it does not show up using the normal ABO blood type tests.

      DNA paternity tests are still accurate (99.999%) with type hh blood and are considered the only accurate test for paternity.

      Best,
      @MsGreene
      Note: I answer a lot of questions on DrGreene.com, I am the co-founder of DrGreene.com, Dr. Greene’s business partner and wife, but I am not Dr. Greene, nor am I a doctor. Please keep that in mind when reading my comments and replies.

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  151. Rebecca

    Is it possible for 0+ and 0- to have a a+ baby

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    • Rebecca,

      Our current understanding of genetics is that it is not possible for one parent to be O-, the other parent to be O+ and their child to be A+. Two type O parents can only have a child who is type O.

      It is wise to have all your blood retested. It’s not uncommon for blood types to be different than they are thought.

      @MsGreene
      Co-founder & Executive Producer DrGreene.com, Mom
      Note: Not Dr. Greene, not a doctor. Keep that in mind when reading my comments and replies.

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  152. JOSEPH

    Hello my wife is B- and my son is O-, what could I be thank you Dr greene

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    • Joseph,

      If the mother of your child is B- and your son is O-, you could be A+, A-, B+, B-, O+ or O-. You could not be Ab+ or AB-.

      Let me know if you’d like further explanation.

      Best, @MsGreene
      Note: I answer a lot of questions on DrGreene.com, I am the co-founder of DrGreene.com, Dr. Greene’s business partner and wife, but I am a not doctor. Please keep that in mind when reading my comments and replies.

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  153. Ann

    Hi dr green I’m Ann I was wondering about 2 years go when I was pregnant I had a blood type test taken it came back that I was B positive and my mum told the dr that she and my dad are both are O positve how can that be the dr just looked at me as if there might be a another reason to why. The hospital did my blood type again and it came back B positive again is this possible even though when I was born they crossed matched my mum blood to Mach me for a blood transfusion as a breammacher baby by 4 months early please email me thank you Ann

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    • Ann,

      Have both your mom and dad’s blood been retested? It’s not uncommon for blood types to be different than they are thought.

      Our current understanding of genetics is that it is not possible for two parents with O+ blood to have a child that is B+. Two O+ parents can only have children who are O+ or O-.

      The only test to determine paternity is a DNA test. Here is a link to one example of a DNA paternity test. They are 99.999% accurate and you can take them in the privacy of your own home. The results are mailed back fairly quickly.

      I hope that’s helpful,

      @MsGreene
      Co-founder & Executive Producer DrGreene.com, Mom
      Note: I answer a lot of questions on DrGreene.com, I am the co-founder of DrGreene.com, Dr. Greene’s business partner and wife, but I am not Dr. Greene, nor am I a doctor. Please keep that in mind when reading my comments and replies.

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      • Ann

        Hi degreen no my mum and dad have been retested my mum is differently o positive and my dad side he’s very sure is o positive should we do a DNA test . Thanking you Ann

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        • Ann,

          A DNA test is 99.999$ accurate in determining paternity. It sounds like that’s your next move.

          Best, @MsGreene
          Note: I answer a lot of questions on DrGreene.com, I am the co-founder of DrGreene.com, Dr. Greene’s business partner and wife, but I am a not doctor. Please keep that in mind when reading my comments and replies.

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      • Ann

        Thank so much I think we will deffirntly give that go

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  154. Mandy

    Thank you so much for an explanation that I could actually understand!!

    My husband is type AB- I am O- and our son is A+

    Our doctor insisted that he could not be ours and forced a DNA test on all 3 of us to prove he was ours. It was a hugely traumatic time and we weren’t allowed to see him or take him home until this had been performed. (Especially because just hours before this doctor saw my son come out of my body!!)

    My husband and I tried researching but it got to a point where all I understood were the “the’s and the and’s” so we didn’t get very far. I’m so glad to have come across this today!!

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  155. PAUL

    Hello DrGreene,
    is it possible for a father of A+ and a mother of B+ to give birth to a child of O+ ?

    Thanks for your anticipated response

    Paul

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    • Paul,

      Yes, it is possible for one parent to have type A+ blood, the other parent to have type B+ blood and their child to have type O+ blood.

      If you’d like an explanation, please let me know.

      Best, @MsGreene
      Co-founder & Executive Producer DrGreene.com, Mom
      Note: Not Dr. Greene, not a doctor. Keep that in mind when reading my comments and replies.

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  156. L

    Thanks for this explanation. I have always wondered if my dad was my real dad, since he and my mom has O positive blood type and I am O negative.

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  157. Lala

    Hi,my blood groub o my husband b and my son b but another male in my life o who is the father to my son and can amutation change ablood groub from parents to child

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    • Lala,

      One type O parent and one type B parent, can have a child that is type B. Two type O parents can not have a child that is type B.

      Mutations are extremely rare.

      The only accepted test for paternity is a DNA test such as this one.

      Best,
      @MsGreene
      Co-founder & Executive Producer DrGreene.com, Mom
      Note: I answer a lot of questions on DrGreene.com, I am the co-founder of DrGreene.com, Dr. Greene’s business partner and wife, but I am a not doctor. Please keep that in mind when reading my comments and replies.

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  158. Cuddles

    I was told by mistake that my dad wasn’t my dad when I was 15 by my sister then she said it cause she was angry,I recently gave blood and found out I’m a b positive ,my dad has passed away but does that mean that one of my parents have to be a b.

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    • Cuddles,

      I’m so sorry for your loss and even sorrier that this is now coming up as an issue for you.

      If you are B+ one of your parents is B+, B-, AB+ or AB-. Bottom line, the B has to come from one of your parents.

      I hope that helps,

      @MsGreene
      Note: I answer a lot of questions on DrGreene.com, I am the co-founder of DrGreene.com, Dr. Greene’s business partner and wife, but I am not Dr. Greene, nor am I a doctor. Please keep that in mind when reading my comments and replies.

      Added:
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  159. Erica

    Could be possible im o+ and my hubby is a could be possible if my daughter is b+?

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    • Erica,

      Our current understanding of science is that it is not possible for one parent to have type O blood, the other parent to have type A blood and have a child that has type B blood.

      It is wise to have all your blood retested. It’s not uncommon for blood types to be different than they are are thought to be.

      @MsGreene
      Co-founder & Executive Producer DrGreene.com, Mom
      Note: Not Dr. Greene, not a doctor. Keep that in mind when reading my comments and replies.

      Added:
      Reply
  160. Harold

    Two strange situations here. My wife’s father was AB+ and her mother was O+. My wife’s blood type is O+. Genetic testing shows that both her parents are her biological parents. We didn’t think this was possible, yet it is. Second situation. I am O+ and my wife is O+. We have three sons. The oldest is O-. The second son tested O+ at birth. The third son is O-. When my second son’s blood was retested a couple of days ago, he tested O-. Is this possible? Could you explain these two situations to me? Thanks for the help.

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  161. Diianna Harrold

    Can an a negative father and a o positve mother have a o positive child

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    • Dilanna,

      Yes, if the father is negative and the mother is positive, they can have a child who is positive. Actually, it doesn’t matter which parent is positive or negative. If one parent is positive and the other is negative, they can have either a positive or a negative child.

      Best, @MsGreene
      Note: I answer a lot of questions on DrGreene.com, I am the co-founder of DrGreene.com, Dr. Greene’s business partner and wife, but I am a not doctor. Please keep that in mind when reading my comments and replies.

      Added:
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  162. Abbey

    Can a mother with a+ and a father with ab+ make a b- baby ??

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    • Hi Abbey,

      Yes, a mother with A+ blood and a father with AB+ can have a child with B- blood.

      Hope that helps,
      @MsGreene
      Co-founder & Executive Producer DrGreene.com, Mom
      Note: Not Dr. Greene, not a doctor. Keep that in mind when reading my comments and replies.

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  163. Samantha Collins

    My sister is O+ve and I am AB-ve is this possible for full siblings?

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    • Samantha,

      Yes, if one parent is A+ or A- and the other is B+ or B-, they can on child who is AB- and one child who is O+.

      If you’d like an explanation, please let me know.

      Best,
      @MsGreene
      Co-founder & Executive Producer DrGreene.com, Mom
      Note: Not Dr. Greene, not a doctor. Keep that in mind when reading my comments and replies.

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  164. Kim

    My mother is A- my father is A+ I’m O+ is the possible?

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    • Hi Kim,

      Yes, this is possible and even common.

      Let me know if you’d like further explanation.

      Best,
      @MsGreene
      Co-founder & Executive Producer DrGreene.com, Mom
      Note: Not Dr. Greene, not a doctor. Keep that in mind when reading my comments and replies.

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  165. Tammy

    Hello I was wondering if my father is A positive and my mother is ab positive is it possible to have a ab negative baby

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    • Tammy,

      Yes, it is possible for an A+ parent and an AB+ parent to have an AB- child.

      Let me know if you’d like an explanation of how this can happen.

      Best,
      @MsGreene
      Co-founder & Executive Producer DrGreene.com, Mom
      Note: Not Dr. Greene, not a doctor. Keep that in mind when reading my comments and replies.

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      • Tammy

        Thank you so much… you have answered all my questions…

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        • You are most welcome!

          @MsGreene
          Note: I answer a lot of questions on DrGreene.com, I am the co-founder of DrGreene.com, Dr. Greene’s business partner and wife, but I am a not doctor. Please keep that in mind when reading my comments and replies.

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  166. James

    Is it possible if wife blood type is O
    husband believe he has blood type is O – since both his parent bloody type is O
    daughter have blood B+ is that possible?

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    • James,

      Our current understanding of genetics is that it is not possible for two type O parents to have a child that is type B. Two type O parents can only have type O children.

      It is wise to have all your blood retested. It’s not uncommon for blood types to be different than they are thought to be.

      @MsGreene
      Co-founder & Executive Producer DrGreene.com, Mom
      Note: Not Dr. Greene, not a doctor. Keep that in mind when reading my comments and replies.

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      • James

        Thanks so much @MsGreene
        really appreciate for writing back to me.

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  167. Shruthi

    Hello,

    My father is A+ve and we our siblings have below blood groups;
    1st child A+ve
    2nd Child O-ve
    3rd child A-ve
    4th Chile A+ve

    Is it possible to have these, also could you please let me know what would be my mother’s blood group.

    Added:
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    • Hello Shruthi,

      Yes, this is a possible outcome. If one parent is A+ and the other is either A+, A-, B+, B-, O+ or O-. The only group the other parent could not be is AB+ or AB-.

      Let me know if you’d like an explanation.

      Best, @MsGreene
      Co-founder & Executive Producer DrGreene.com, Mom
      Note: I answer a lot of questions on DrGreene.com, I am the co-founder of DrGreene.com, Dr. Greene’s business partner and wife, but I am a not doctor. Please keep that in mind when reading my comments and replies.

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  168. Ashley

    If I am o negative and my baby is o negative what is my husbands blood type?

    Added:
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    • Hi Ashley,

      If you are O- and your baby is O-, the baby’s father could be O+, O-, A+, A-, B+ or B-. He could not be AB+ or AB-.

      If you’d like an explanation, please let me know.

      Best, @MsGreene
      Co-founder & Executive Producer DrGreene.com, Mom
      Note: Not Dr. Greene, not a doctor. Keep that in mind when reading my comments and replies.

      Added:
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  169. Toni

    My family did a home blood test, eldon card kit. I am AB+, my husband is O+, our eldest daughter is A+ and our youngest daughters test said O+. We retested her because I read that AB+ and O+ parents cannot have an O+ child. After retesting we got the same results. No agglutination is anti-A or anti-B. Another O+. Is that even possible? At all? Even a small chance? I will say she is a very unique child haha- but she is definitely the product of my husband and I. I know my husband and my own blood types are correct, this was just for the kids and for a little science experiment.

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    • Toni,

      You are correct, an AB+ parent can not have a child who is O+. You may want to retest your blood types with a clinical lab.

      If the results are the same, you might consider a DNA paternity test, though in this case it would be a maternity test. You can buy the kits online. Here’s one example. They are 99.999% effective.

      @MsGreene
      Co-founder & Executive Producer DrGreene.com, Mom
      Note: I answer a lot of questions on DrGreene.com, I am the co-founder of DrGreene.com, Dr. Greene’s business partner and wife, but I am a not doctor. Please keep that in mind when reading my comments and replies.

      Added:
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      • Smith

        This is disgraceful if you really knew what you were talking about you would have heard of the Bombay blood group where AB parents can have what appear to be O children. It is rare but coming from a family with Bombay blood I happen to know about it. My question to you is: why don’t you rather than frightening people into thinking that they are not true offspring?

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        • Smith,

          Thanks for your comment. I love to learn and will delve into the Bombay blood group research. My current understanding it that it is extremely rare and DNA tests (which I strongly suggest to people who have questionable combinations) are still 99.999% accurate.

          Best,
          @MsGreene
          Co-founder & Executive Producer DrGreene.com, Mom
          Note: Not Dr. Greene, not a doctor. Keep that in mind when reading my comments and replies.

          Added:
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          • Hi Smith,

            I’ve done some research and think I have a better handle on this. I tried to email you to discuss, but the email address you provided bounced. If you’d like to discuss more, please reach out again.

            Best,
            @MsGreene
            Co-founder & Executive Producer DrGreene.com, Mom
            Note: Not Dr. Greene, not a doctor. Keep that in mind when reading my comments and replies.

            Added:
    • Toni,

      There is a possible explanation after all (thanks Smith for pointing this out in your comment below).

      There is a very rare blood type (0.0004% or about 4 per million in the general population) known as the Bombay Blood type. In some places such as Mumbai (which was formerly called Bombay) the occurrences can be as high as 0.01% or 1 in 10,000. This group does not fall into the ABO system and the usual tests for ABO blood show them as group O.

      The Bombay blood type is usually only found in small communities where there are other people with the hh blood type. Both parents have to be h carriers, though a parent can be a carrier without actually having Bombay type blood.

      If you suspect your child may have the Bombay blood type talk to your doctor about a specialized test for this blood type as it does not show up using the normal ABO blood type tests.

      DNA paternity tests are still accurate (99.999%) with type hh blood and are considered the only accurate test for paternity.

      Best,
      @MsGreene
      Note: I answer a lot of questions on DrGreene.com, I am the co-founder of DrGreene.com, Dr. Greene’s business partner and wife, but I am not Dr. Greene, nor am I a doctor. Please keep that in mind when reading my comments and replies.

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  170. lisa

    My mother is o+ and im b+ what would my fathers bloof type be?

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    • Lisa,

      If your mother is O+ and your father is B+, you could be O+, O-, B+ or B-.

      If you’d like an explanation, please let me know.

      Best,
      @MsGreene
      Co-founder & Executive Producer DrGreene.com, Mom
      Note: Not Dr. Greene, not a doctor. Keep that in mind when reading my comments and replies.

      Added:
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  171. Mariam

    My blood type is A,my daughter’s blood type is N, what should her father’s blood type be?

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  172. Michelle

    Hi,
    My mother is type A positive and I am type A RH negative. What would my father need to be?
    Thank You

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    • Hi Michelle,

      If your mother is A+ and you are A-, your father could be A+, A-, B+, B-, O+, O-, AB+ or AB+. Basically, no blood types are eliminated with this combination.

      If you’d like an explanation, let me know.

      Best, @MsGreene
      Co-founder & Executive Producer DrGreene.com, Mom
      Note: I answer a lot of questions on DrGreene.com, I am the co-founder of DrGreene.com, Dr. Greene’s business partner, but I am a not doctor. Please keep that in mind when reading my comments and replies.

      Added:
      Reply
  173. christal

    I need to knoe if two parents are o postive and already have a child 0 postive and have a second child but that baby is a pos is that a possibility

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    • Christal,

      Our current understanding of science is that it is not possible two parents who are O+ to have a child that is A+. If one parent is O+ and the other is A+ or A-, it would be possible for them to have one child who is A+ and another child who is A+.

      It is wise to have all your blood retested. It’s not uncommon for blood types to be different than they are remembered.

      @MsGreene
      Co-founder & Executive Producer DrGreene.com, Mom
      Note: Not Dr. Greene, not a doctor. Keep that in mind when reading my comments and replies.

      Added:
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      • Chinna

        Is it possible both parents blood group is O positive and child is A positive blood group ?

        Added:
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        • Chinna,

          If a child is A+, both of her parents can not be O+.

          It is not uncommon for one of the blood types to be different than thought, so it is wise to have all three types retested.

          Best, @MsGreene
          Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  174. Viky

    Hi doc. My mother blood group is O+ and my father B+. And my blood group is O-. Is it possible?😐

    Added:
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    • Hi Viky,

      Yes, it is possible for one parent to be O+, the other parent to be B+ and the child to be O-.

      If you’d like an explanation, let me know.

      Best, @MsGreene
      Co-founder & Executive Producer DrGreene.com, Mom
      Note: I answer a lot of questions on DrGreene.com, I am the co-founder of DrGreene.com, Dr. Greene’s business partner, but I am a not doctor. Please keep that in mind when reading my comments and replies.

      Added:
      Reply
  175. Unknown

    Can an A+ and O make a child of A+

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    • Unknown,

      Yes, this is a possible outcome.

      If you’d like an explanation, please let me know.

      @MsGreene
      Co-founder & Executive Producer DrGreene.com, Mom
      Note: I answer a lot of questions on DrGreene.com, I am the co-founder of DrGreene.com, Dr. Greene’s business partner, but I am a not doctor. Please keep that in mind when reading my comments and replies.

      Added:
      Reply
  176. Unknown

    Hi, my blood type is the same as my mom but not my dad. My second oldest sister is the same as my dad. To me I have no father at all. I really don’t see features of me in him at all, but force myself to believe. My mom I feel has been hiding so much since I was a little girl. I have traumatic brain injury since 2013 from assault by her boyfriend. But, I still don’t see me in my dad. I found my dad in 2006. I have no recollection of him at all. My mom and him try to force memories on me that I don’t know. I didn’t see my dad from age two or three until I was almost 29.

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    • Unknown,

      If you want to have a real confirmation that he is your father, a DNA paternity test is in order. They are 99.999% accurate. Here is one example of a DNA paternity test you can buy online. The two of you can take the test at home and mail it in, so you don’t even need to go to a lab.

      I hope this helps, @MsGreene
      Co-founder & Executive Producer DrGreene.com, Mom
      Note: I answer a lot of questions on DrGreene.com, I am the co-founder of DrGreene.com, Dr. Greene’s business partner, but I am a not doctor. Please keep that in mind when reading my comments and replies.

      Added:
      Reply
  177. Trisha

    i’m at a lost. My whole life, since I can remember, my siblings would joke I was adopted. I gave blood at 17 years old and found out I’m O+. My dad is AB+ and my mom is A+. My sisters are A+. Please help me figure out how that is possible? I’d ask them but I’m too scared to.

    Added:
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    • Trisha,

      Our current understanding of genetics is that it is not possible for one parent to be AB+, the other parent A+ and a child that is O+. An AB parent can only have children who are A, B or AB. An AB+ parent and an A+ parent can have children who are A+, A- B+, B-, AB+ or AB-.

      I know this would require discussing it with your parents, but it is wise ask them. If they say you are their biological child, ask to have all your blood retested. It’s not uncommon for blood types to be different than they are remembered.

      @MsGreene
      Co-founder & Executive Producer DrGreene.com, Mom
      Note: I answer a lot of questions on DrGreene.com, I am the co-founder of DrGreene.com, Dr. Greene’s business partner, but I am a not doctor. Please keep that in mind when reading my comments and replies.

      Added:
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  178. Susie Gresham

    Hi, not sure if my question posted or not. Can a O positive person and a Rh negative person have a A positive baby?

    Added:
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    • Susie Gresham

      So are you saying yes or no?

      Added:
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      • Susie,

        I’m sorry. There was a very confusing error in my last answer to you. I’ve edited it, but here it is (to make it easier for you to find what is changed):

        Blood types have two identifiers. The first is A, B, O or AB. The second is Rh+ or Rh-, which we simply call + or – after the letter. As an example, O+.

        You don’t seem to know if the person you list as “Rh-” is A-, B-, O- or AB-. If that parent is A- or AB- then the answer is yes, it is possible. But if the second parent is O-, or B- the answer is, no.

        Best, @MsGreene
        Co-founder & Executive Producer DrGreene.com, Mom
        Note: I answer a lot of questions on DrGreene.com, I am the co-founder of DrGreene.com, Dr. Greene’s business partner, but I am a not doctor. Please keep that in mind when reading my comments and replies.

        Added:
        Reply
  179. Sanjhna

    My blood group is B-ve and my husband’s blood group is O+ve. My newborn baby is having B+ ve. I am confuse Is that possible. Lab technician said its rare??

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    • Lalita

      Hello Dr. Greene,

      My sister recently gave birth to a baby boy. She is bit confuse about her babies blood group who is B+ve. she is B-ve and her husband is O+ve. Is that possible??

      Added:
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      • Lalita,

        Yes, that is completely normal. If you’d like an explanation, let me know.

        Best, @MsGreene
        Note: I answer a lot of questions on DrGreene.com, I am the co-founder of DrGreene.com, Dr. Greene’s business partner, but I am a not doctor. Please keep that in mind when reading my comments and replies.

        Added:
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    • Sanjhna,

      Yes, it is possible for one parent to be B- the other to be O+ and the baby to be B+. There is nothing to worry about.

      By rare, she just means it is not as common as O+ blood types. This doesn’t not mean your child has any additional risk of health issues based on blood type. The only time this would be an issue is if your baby needs a blood transfusion as this blood type is not as common as others, it might be harder to find.

      Best,
      @MsGreene

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  180. Robin

    My parents, grandparents, and 2 brothers are o positive. I am b negative. How is this possible?

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    • Robin,

      Our current understanding of genetics is it is not possible for two O+ parents to have a child that is B-.

      It is wise to have all your blood retested. It’s not uncommon for blood types to be different than they are remembered.

      @MsGreene
      Co-founder & Executive Producer DrGreene.com
      Note: I answer a lot of questions on DrGreene.com, I am the co-founder of DrGreene.com, Dr. Greene’s business partner, but I am a not doctor. Please keep that in mind when reading my comments and replies.

      Added:
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  181. deb kelly

    Can a a- and a+ have a b-

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    • Deb,

      Our current understanding of science is that it is not possible for one parent to be A-, the other parent A+ and their child to be B-.

      It is wise to have all your blood retested. It’s not uncommon for blood types to be different than they are remembered.

      Best, @MsGreene
      Note: I answer a lot of questions on DrGreene.com, I am the co-founder of DrGreene.com and Dr. Greene’s business partner, but I am a not doctor. Please keep that in mind when reading my comments and replies.

      Added:
      Reply
  182. Lakshmi

    My blood group is b+be,my husband blood group is ab-be and daughter blood group is ab+be is it possible.

    Added:
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    • Lakshmi,

      Yes, that is a possible outcome.

      Let me know if you’d like an explanation.

      Best, @MsGreene
      Note: I answer a lot of questions on DrGreene.com, I am the co-founder of DrGreene.com and Dr. Greene’s business partner, but I am a not doctor. Please keep that in mind when reading my comments and replies.

      Added:
      Reply
  183. Rhonald Mitchell

    My dad is O and my mum is RH negative why am I AB positive

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    • Rhonald,

      Our current understanding of science is that it is not possible for one parent to have type O blood and have a child that is type AB. An AB parent can only have children who are A, B or AB.

      It is wise to have both your blood retested. It’s not uncommon for blood types to be different than they are remembered.

      @MsGreene
      Co-founder & Executive Producer DrGreene.com
      Note: I answer a lot of questions on DrGreene.com, I am the co-founder of DrGreene.com, Dr. Greene’s business partner, but I am a not doctor. Please keep that in mind when reading my comments and replies.

      Added:
      Reply
  184. Rachel

    Hi there, is it possible for siblings to each have completely different blood types, I am B Rh(D) positive, my older brother is B negative and my younger brother is O positive. We think our Dad is bloody type O. My older brother had blood transfusion as a baby, does this effect it?

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    • Rachel,

      If one parent has type O blood and his or her children are B+, B- and O+, the other parent would be type B (likely B+, but could be B- if the first parent is O+).

      I hope that’s helpful, @MsGreene
      Note: I answer a lot of questions on DrGreene.com, I am the co-founder of DrGreene.com, Dr. Greene’s business partner, but I am a not doctor. Please keep that in mind when reading my comments and replies.

      Added:
      Reply
  185. Korine

    Hi,

    My husband is has the blood type A+ and I have B+. We had a baby that was tested AB+ when he was born and four years later B+. Is it normal for a blood type to change?

    Thank you

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    • Korine,

      It is not normal for a blood type to change, but it is not at all unusual for blood type tests to be inaccurate.

      Best,
      Co-founder & Executive Producer DrGreene.com, Mom
      Note: Not Dr. Greene, not a doctor. Keep that in mind when reading my comments and replies.

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  186. Korine

    Hi,

    My husband have the blood type A+ and and I have B+. We had a baby boy who is A -. The Rhesus – could be a problem for him?

    Thank you

    Added:
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    • Korine,

      It is possible for two parents with Rh+ blood to have a child that is Rh-. This should not cause a problem for the child.

      Best,
      Co-founder & Executive Producer DrGreene.com, Mom
      Note: Not Dr. Greene, not a doctor. Keep that in mind when reading my comments and replies.

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  187. Jorge Leon

    Hello

    Mother is O positive and father is AB positive . Baby is A positive with anti RhD positive antibodies
    Is this possible ?

    Thanks !

    George

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    • Jorge,

      Yes, this is a possible scenario. Baby got an A from dad and an O from mom, making baby A.

      Let me know if you’d like an explanation.

      Best,
      @MsGreene
      Co-founder & Executive Producer DrGreene.com, Mom

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  188. Ruby G

    Hi my Name is Ruby

    My blood type is B-
    But my parents blood types are Mother B+ and Dad O+
    is this possible ?

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    • Ruby,

      Yes it is possible for a child to be B- if his or her parents are B+ and O+.

      If you’d like an explanation, please let me know.

      Best, @MsGreene
      Note: I reply to a lot of the comments on DrGreene.com, I am the co-founder of DrGreene.com and Dr. Greene’s business partner, but I am a not doctor. Please keep that in mind when reading my comments and replies.

      Added:
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  189. Charlie McAdams

    I’m a+ my husband is a something and our daughter is 0- possible???

    Added:
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    • Charlie,

      Yes, it is possible for an A+ mother to have an O- child.

      Let me know if you’d like an explanation.

      Best, @MsGreene
      Note: I reply to a lot of the comments on DrGreene.com, I am the co-founder of DrGreene.com and Dr. Greene’s business partner, but I am a not doctor. Please keep that in mind when reading my comments and replies.

      Added:
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  190. edilyn

    hello :) my mother is blood type A and my father is blood type O and me is blood type b+ it could be their my real parents ?

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    • Edilyn,

      Our current understanding of science is that it is not possible for one parent to be A, the other parent O and a child that is B.

      It is wise to have all your blood retested. It’s not uncommon for blood types to be different than they are remembered.

      Best, @MsGreene
      Note: I reply to a lot of the comments on DrGreene.com, I am the co-founder of DrGreene.com and Dr. Greene’s business partner, but I am a not doctor. Please keep that in mind when reading my comments and replies.

      Added:
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  191. Flora

    Hello :) if i am is blood type 0 then my son is blood type b? What could be my husband’s bloodtype? Thanks

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    • Flora,

      If your blood type is O and your son’s blood type is B, the father must be B.

      People with type O blood, unlike A and B, can only pass down an O allele. As can pass down an A or an O. Bs can pass down a B or an O. ABs can pass down an A or a B.

      Best,
      @MsGreene

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  192. liz

    Hi dr. I just recently gave birth. My husband and I are both A+. But now my 2nd baby who exactly looks like my 1st born have O+??? How is it even possible? I checked with the hospital and said it is the correct blood type? Pls advise. Thanks

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    • Liz,

      Blood types are determined by two alleles. People who have type A blood can either have two A alleles (AA) or one A and one O (AO). Both are called type A. It sounds like in your situation, both parents are AO and each one passed down the O allele, so the baby is O.

      Does that make sense?

      @MsGreene

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      • liz

        Yes, now that u said it. Thanks a lot :)

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  193. Angela Giles

    Mother’s bg =A negative and
    Fathers bg=A+.
    2x siblings have A+ and 1x sibling has AB + .Is this possible

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    • Angela,

      Our current understanding of science is that it is not possible for two parents with type A blood to have a child that is type AB.

      It is wise to have both parents and the child you think is AB retested. It’s not uncommon for blood types to be different than they are remembered and if one of the parents was type B instead of type A, all this would be perfectly normal.

      @MsGreene
      Co-founder & Executive Producer DrGreene.com, Mom

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  194. sonia

    hi i m sonia… plz tell me if father blood group is B+ n mother blood group is A+ den child can be o negitive?

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    • Sonia,

      Yes, if one parent is B+ and the other is A+, it is perfectly normal for their child to be O-.

      If you’d like an explanation, please let me know.

      Best,
      @MsGreene

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  195. sandy

    I have the same question about my parents if neither have rh- blood. my dad had o+ and I think my mother had the same. I didn’t know I had rh A – until I was pregnant with my second child. I then had to take a shot to lessen another baby having my blood type after my son was born. Both kids did not have my blood type. I had two more kids with no problems. I wasn’t told until way later own I shouldn’t have more children because of my blood type. I always had the question of how I got my type blood. I am the middle daughter of six brothers and no sisters. None of my brothers have my blood type. I spent a lot of years wondering how I got it. and felt I didn’t belong. I guess I want just plain English that I belong to my parents. All this plus and minus blood types are confusing.

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  196. Stefanie lee

    Hello i need to asks why my Bro and I have share same blood group type of B positive while my mom is A positive and my dad is O positive?

    Added:
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    • Stefanie,

      Our current understanding of science is that it is not possible for one parent to be A+, the other parent O+ and a child that is B+.

      It is wise to have all your blood retested. It’s not uncommon for blood types to be different than they are remembered.

      @MsGreene
      Co-founder & Executive Producer DrGreene.com, Mom

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      • Andrew Khoury

        It is possible under one condition, which is mutation by recombination. This was published in a study by Stanford University by Nathalie Dye. Mutations are very likely to occur. I’ve had extensive research on this topic where such blood types occurred and with specific laboratory testing, proving that it is possible when DNA tests showed both parents to have an offspring of a different blood type.

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      • Stefanie Lee

        Just found out I’m not theirs biological….25 years!!!!they have been kept it secret for 25years….I dont feel so great…..wonder where is my biological parent are and how does they looks like…..should I searched for them…..or just stay as usual pretend nothing happens?

        Added:
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        • Stefanie,

          It sounds like this has hit you very hard. The decision to search for one’s biological parents is a personal one. It helps some people, but not everyone.

          It is often helpful for adopted children to discuss the situation with this adopted parents and try to understand their perspective. In the process, it may be very helpful to talk with a counselor to help work through the feelings associated with this kind of revelation.

          Sincerely, @MsGreeene
          Co-founder & Eecutive Producer, DrGreene.com
          Note: I answer a lot of questions on DrGreene.com, I am the co-founder of DrGreene.com, Dr. Greene’s business partner and wife, but I am a not doctor. Please keep that in mind when reading my comments and replies.

          Added:
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          • Stefanie Lee

            Guess will try to talk to someone before searching for the biological parents. I just need some time to digest the fact I’m their adopted daughter.

            Added:
  197. Adonis

    Is it possible to have a B blood type if my parents have O and O…?

    Added:
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    • Adonis,

      Our current understanding of science is that it is not possible for both parents to have type O blood and their child to have type B blood. Two type O parents can only have a type O child.

      It is wise to have all your blood retested. If one of your parents was type B or AB, then you could be type B. It’s not uncommon for blood types to be different than they are remembered.

      @MsGreene
      Co-founder & Executive Producer DrGreene.com, Mom

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  198. Salma Ahmad

    Hi Dr greene my name is salma
    my father BG is A+ my mother BG is A+ .we are 4 siblings my 3 siblings have BG A+ while i m having BG B+ ..is it Possible that a child could have such blood group while both mother and father A+ blood group??
    or there may be some mistake in my blood group report ?

    Added:
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    • Hi Salma,

      Our current understanding of science is that it is not possible for two parents with A+ blood group to have a child that is B+.

      It is wise to have all your blood retested. It’s not uncommon for blood types to be different than they are remembered.

      @MsGreene
      Co-founder & Executive Producer DrGreene.com, Mom

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  199. Danni

    My mothers bloodtype was a-, fathers bloodtype is b+ my bloodtype is O+ does this make sense? Only recently we found out that one father was not the same as another sibling who had a- mother a- her father a+ bloodtypes…maybe I’m just being paranoid but that was over thirty years of a lie. I just want to know if mine makes sense?

    Added:
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    • Danni,

      If your mother’s blood type was a-, your father’s blood type is b+, it is possible for your blood type to be O+.

      If you’d like an explanation, let me know.

      @MsGreene

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  200. Mary

    Hello, my mother was O+ and her husband was AB-. I have six sibling: their blood types: brother AB- , brother AB-, brother B-, sister O- , brother B+, brother O- and I have O+ . My mother told me before she died that my father was her landlord’s 19 year old son. Could AB- and an O+ have an O+ child?
    Thank you for any help.

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    Reply
    • Mary,

      Our current understanding of science is that it is not possible for one parent to be AB-, the other parent O+, and have a child that is O+. An AB+ parent and an O+ parent can only have children who are A+, A-, B+ or B-.

      @MsGreene
      Co-founder & Executive Producer DrGreene.com, Mom

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  201. Emma Ibbitson.

    Hello Dr Greene,

    I have spent countless hours searching for an answer to me shall I call it, predicament. See I am a B Rhesus Neg. My Mum was a O+ and my dad was I believe a A+. This is where it gets confusing for me. I have four other siblings, none of them share the same blood group as me. I have asked my Mum (before she passed awäy 2 years ago) why my blood is different to my siblings and she couldn’t answer. I cannot ask my Father as he passed away when I was very young. Could it be a genetic mutation or like people keep telling me, I may have a different Father. I know my BG is correct as I’ve had all the D injections etc. Now I have no one left to ask, I feel lost.

    Added:
    Reply
    • Emma,

      I’m so sorry you have no one left to ask. Often in these situations, someone’s blood type is different that thought. For instance, if your father was B+ or B-, and your mother was O+, you could be B-.

      Best,
      @MsGreene

      Added:
      Reply
  202. Ella

    My mother is O+ and my father is B+, and I am B-, is he my father that gave birth to me.?

    Added:
    Reply
    • Hi Ella,

      If your mother has O+ blood and you have B- blood, it is possible that your birth father has B+ blood.

      Some times, blood types can rule out a potential father, but they can not determine paternity. The only way to determine if he is your birth father is to take a DNA paternity test. They are 99.999% accurate.

      Good luck on your search,
      @MsGreene

      Added:
      Reply
  203. Christy

    Hello dr. My blood type is o neg my husband is o pos and my oldest and youngest daughter are o pos. Me and my husband weren’t together when i got pregnant with my youngest the other male is bpos could the other male be my daughters father or my husband?

    Added:
    Reply
    • Christy,

      These blood types don’t exclude either possible father. If you really want to know, DNA paternity testing is 99.999% accurate.

      Best,
      @MsGreene

      Added:
      Reply
  204. Elaine Reiser

    Hi Dr. Greene. There has always been a question of my paternity and today I finally got the answer that I needed. My father is B+ and my mother is B+, I am AB+. I conclude that my “father” is really not my biological father. Is that what you would suppose also?
    Thanks,
    Elaine

    Added:
    Reply
    • Elaine,

      First, blood types are often different that what they are thought to be. Possibly an error in the test or in the recording. But, our current understanding of science is that it is not possible for two B+ parents to have an AB+ child.

      I hope this is helpful,
      @MsGreene

      Added:
      Reply
  205. Jb

    Hi dr. Greene,

    My name is jb frm phillipines, i want to know that is there a
    Possible that my family have 3 blood type. My father is O+, my mothere is A+. We are 5 their children, we r 4 girls n 1 elder brother.
    3 of my sister are blood type is A+, my brother is AB+, then my blood type is B+. Can u xplain this to me, kindly plss i need the explanation about this plss help me. Thank u very much if u give me short time for this Godbless

    Added:
    Reply
    • JB,

      For a child to be AB the parents must be A and B, or AB and A, or AB and B. According to our current understanding of genetics, an O parent can not have an AB child. Also an O parent and an A parent can not have a B child.

      Before you jump to any conclusions, it’s wise to have everyone’s blood retested. For more accuracy, you can do DNA paternity tests that are 99.999% accurate.

      Best,
      @MsGreene

      Added:
      Reply
  206. Kate

    Hello, my father was AB neg and my mother was O pos. My two sisters are A neg and B neg respectively. I am rhesus neg O is that possible?. Really need to know thanks.

    Added:
    Reply
    • Kate,

      Our current understanding of science is that it is not possible for one parent to be AB-, the other parent O+ and a child that is O-. An AB parent can only have children who are A, B or AB.

      It is wise to have all your blood retested. It’s not uncommon for blood types to be different than they are remembered.

      @MsGreene
      Co-founder & Executive Producer DrGreene.com, Mom

      Added:
      Reply
  207. Steph

    My mother is B+ and my father is O+ . I am AB+ can my father be my father?

    Added:
    Reply
    • Steph,

      Our current understanding of science is that it is not possible for one parent to be B+, the other parent O+ and a child that is AB+. The only blood types a child can have if the parents are B+ and O+ are O+, O-, B+,or B-.

      It would be wise to have all your blood retested. It’s not uncommon for blood types to be different than they are remembered.

      @MsGreene
      Co-founder & Executive Producer DrGreene.com, Mom

      Added:
      Reply
  208. Lyn cook

    I have two daughters with rhesus neg blood type does this mean my other three will have the same,one daughter is in a turmoil that her dad isn’t her dad after all?

    Added:
    Reply
    • Lyn,

      No you can not assume that if two siblings are Rh-, the other three are Rh-, unless you know both parents are Rh-.

      If one parent is Rh+ and the other is Rh+ or Rh-, they can have children that are either Rh- or Rh+.

      The best way to determine paternity is a DNA paternity test. You can purchase these online and collect DNA samples at home, then send the tests away to a lab. They are 99.999% accurate.

      Best,
      @MsGreene

      Added:
      Reply
      • Lyn cook

        Thankyou for that reply. I am o+ not sure of my husband. So my kids could be different blood types?

        Added:
        Reply
        • Lyn,

          Blood types are determined by both parents, so your kids father’s blood type is very important in determining their blood type.

          Best,
          @MsGreene

          Added:
          Reply
          • Lyn cook

            I am o+my husband says he is A what would that mean for my kids would they all be R-

            Added:
          • Lyn,

            I don’t know what you mean by “R-“. Do you mean “Rh-“. Also, what is your Rh type? Is it + or -?

            Best, @MsGreene
            Note: I answer a lot of questions on DrGreene.com, I am the co-founder of DrGreene.com, Dr. Greene’s business partner, but I am a not doctor. Please keep that in mind when reading my comments and replies.

            Added:
          • Lyn cook

            Still waiting for a reply,,anxious!!

            Added:
          • Lyn cook

            I am 0 positive and my husband says he is A type blood?

            Added:
          • Lyn cook

            Thankyou for those answers,we are grateful and will test our blood groups again.

            Added:
  209. Misti

    Hello Dr. Greene,

    Recently my youngest daughter (19) had her blood type checked, her results came back as B+. I am O- and my husband is A+, I understand that this is not possible according to the charts but I am 100% sure that we are her parents. Furthermore, the hospital she was born in had a stay in the room policy, so when she was born she was with me at all times with the exception of about an hour when she was chocking about 10 hours after birth. What are the possibilities here? I have been reading everything I can but am coming up empty handed.

    Added:
    Reply
    • Misti,

      The most likely possibility one of the blood types is different than you think it is. It is very wise to have all your blood retested. If they still come back as “impossible type”, have DNA tests run.

      Best,

      @MsGreene
      Co-founder & Executive Producer DrGreene.com, Mom

      Added:
      Reply
  210. Saleem Sahar

    Hi dear Doctor,

    My father is O negative, my mother is B negative and my blood group is O positive.
    Could you explain that is possible or not, Please?

    Thanks in advance!

    Added:
    Reply
    • Saleem,

      According to our current understanding of science, two Rh- parents can not have a child who is Rh+. Before you go any further, it would be wise to have everyone’s blood re-tested. If either of your parents are Rh+, you could be O+.

      Best,
      @MsGreene

      Added:
      Reply
      • Ashley RT

        Hi i am A- my dad is O- and my mom is A+ what blood group should my dads parents have?

        Added:
        Reply
        • Hi Ashley,

          If your father is O-, his parent could have been A+, A-, B+, B-, O+ or O-. Neither parent could be AB+ or AB-.

          Best,
          @MsGreene

          Added:
          Reply
          • Ashley RT

            Thanks!

            Added:
          • Ashley RT

            Hi Ms Greene

            Sorry I have one more question, my grandma has A+ and my Grandpa has O+ their son (my Uncle) has O+, my mom has A+ so does that mean that my aunt has to be either O+ or A+?

            Added:
    • Saleem,

      Our current understanding of science is that it is not possible for one parent to be O-, the other parent B- and a child that is O+. Two Rh- parents, can not have a child who is Rh+.

      Very wise to have all your blood retested. It’s not uncommon for blood types to be different than they are remembered.

      @MsGreene
      Co-founder & Executive Producer DrGreene.com, Mom

      Added:
      Reply
  211. Debbie

    You have said it is not possible for an AB parent and an O parent to have an O child. I can say it is so possible, although I’m not sure how.
    My mother is AB Neg. Has been tested many times and she is. She is also surely my mother. My father is O pos. Says so on his dog tags and has been retested. My blood type is O Pos. I’ve been tested multiple times. I also have three other siblings with O pos blood. Only one has been retested.
    According to current understanding I realize this is not suppose to be possible yet here I am. I have heard of Bombay blood type but this does not apply.
    Any ideas on this?

    Added:
    Reply
    • Debbie,

      There are very rare mutation. If this is one, you should go to a major university genetics department and tell your story. If the blood types are confirmed, they may well want to study your family.

      Best,
      @MsGreene

      Added:
      Reply
      • Debbie

        Dr. Greene,
        Thanks for your reply.
        I’ve searched for years for someone to help me understand how this is possible but no one seems interested. Either that or doubt the facts, which are verifiable.
        Any suggestions on who would be interested?

        Added:
        Reply
          • Debbie

            Center Kentucky/Tennessee border. Would be willing to travel if it helps advance science.
            Thanks again.

            Added:
          • Debbie,

            I am unfamiliar with the work of major universities in your part of the country, but there are two things I would suggest:
            1) Have all of the members of your family group take a 23andMe test or other DNA test, such as DNA Paternity Test. This will give you a DNA “fingerprint” that links you to each other. NOTE: Before you purchase any kit like the ones listed above, be sure to contact them and ask the best way to test your entire family and prove your relationship to each other.
            2) Once you have the results, contact major research university near you. Ask for the genetics department and tell them your story. There may not be anyone working on these issues in that department or even that university, but they may know of someone in a different department or different university that they can refer you to as your next step. This may take many phone calls before you find someone who is doing research in this area.

            I hope that’s helpful.

            Best,
            @MsGreene
            Co-founder and Executive Producer, DrGreene.com

            Added:
  212. Maya

    Hello Dr, my mother is A+ My father is O + . My blood type is b + and my brother is Ab + is that possible ? Please i needur help

    Added:
    Reply
    • Dear Maya,

      The combination you describe is not possible given our current understanding of genetics, but it is not unusual for one blood type to be different than what you think it is. For instance, if the mother is A+, one child is B+ and one child is AB+, they could have the same father if he was B+ or B-.

      I hope that’s helpful.
      @MsGreene

      Added:
      Reply
  213. Kathy

    My mother was o positive and my dad is AB neg can they have a child who is AB? Could my mom have an AB child with someone else?

    Added:
    Reply
    • Kathy,

      According to our current understanding of genetics, a parent with type O blood can not have a child with AB blood, no matter what the blood type of the other parent is.

      A child with AB blood can have one parent with A and one with B, or any combination of A, B and AB, i.e. A and AB, B and AB, AB and AB.

      Before jumping to any conclusions, please consider having everyone’s blood re-tested. It is not at all uncommon for blood types to be different than they are remembered.

      I hope that’s helpful.
      @MsGreene

      Added:
      Reply
  214. mumu

    Hello dr.greene
    I want to know that if blood grp is O+ and my wife’s is also O+ but my son’s blood grp is A+..is it possible??

    Added:
    Reply
    • Mumu,

      Our current understanding of science is that it is not possible for both parents to be blood type O+ and a child that is A+ blood type.

      It would be very wise to have all your blood retested. It’s not uncommon for blood types to be different than they are remembered.

      @MsGreene
      Co-founder & Executive Producer DrGreene.com, Mom

      Added:
      Reply
  215. Ria

    Hi.
    Me and my boyfriend is both type B.. my son is type O. But my ex fiance is also type O … but i dont know thier rh.. me is B+..
    Thankss..

    Added:
    Reply
    • Ria,

      I the mother is type B+ and her child is type O, the father could be A+, A-, B+, B-, O+, O-, but not AB+ or AB-.

      If you’d like to know why, let me know.

      Best,
      @MsGreene

      Added:
      Reply
  216. Ariel bohanan

    I have rh o- blood, I’m the mom. My child has o+., what possible blood type would the fathers have? Trying to figure out something before I get a test.

    Added:
    Reply
    • Ariel,

      If the mother is O- and the child is O+, the father could be A+, B+ or O+.

      Also, were you treated for Rh Incompatibility? If not, discuss this with your doctor before getting pregnant again.

      Best,
      @MsGreene
      Co-founder & Executive Producer DrGreene.com, Mom

      Added:
      Reply
  217. Jitendra

    My &my wife blood group are b+ my son also b+ but my daughter o+ its possible

    Added:
    Reply
    • Jitendra,

      Yes, this is possible. If you’d like an explanation of how, let me know.

      Best,
      @MsGreene

      Added:
      Reply
  218. Edward

    Hello Dr. Greene,
    I have two children both O- however my wife and I are both O+
    I understand your explanation above how this is made possible.
    Just wondering though is there also possibilities for blood types to
    skip generation or be inherited? Just asking because my Mother is also
    an O- like my two kids. Im almost certain her parents (my grandparents)
    are both RH+
    Thanks!

    Added:
    Reply
  219. Donna

    I am a B+ and I have a daughter that is B- I do not know her fathers blood type but what would that be? She is now pregnant and they are telling her she may need a shot at different times during the pregnancy because of the negative. I am just wondering where that negative come from and how is that related to pregnancy. The doctor asked If I had to have a shot at pregnancy but I think Id remember that.

    Added:
    Reply
    • Donna

      Thank you so much we will look at the article.

      Added:
      Reply
  220. Claire C

    Hi Dr. Greene,

    My Mother and Father are both A positive (I think) and I am O negative – is this possible?

    Added:
    Reply
    • Claire,

      Yes, it is possible for two parents who are A+ to have a child who is O-.

      If you’d like an explanation, please let me know.

      Best,
      @MsGreene
      Co-founder & Executive Producer DrGreene.com, Mom

      Added:
      Reply
      • Nona

        I would like an explanation, please. I had twin daughter – one is O negative and the other is O positive. Both myself and their father are A positive. Also, when they were born, I am pretty sure the Dr’s told me they were A positive. I am confused. They are 33 yes old.

        Added:
        Reply
        • Marie

          Hi, my blood is rh b- my half sister is rh o- we have same mum different dad, my mums sister is rh o- aswell, but she is my mums half sister , they have same mum different dad. I have 3 children who are all positive as I had anti d with all of them? Is that right, where does the rh- come from?

          Added:
          Reply
  221. Anna Win

    Hello
    Im O negative and my parents are A and/or B positive. Im doing my family tree and so far discovering that im the only one with this blood type. Is this possible? As neither of my parents/family carry my blood type.
    There is currently no evidence of as to how this is possible and i need it cleared up for myself to know. I only discovered my blood type after suffering two miscarriages and being told this is a factor. Please. I need answers, even if its not good.

    Added:
    Reply
  222. Qasim ali

    My blod group is ab- and my wife blod group is o+ it is possible we have a child with o- or its not possible

    Added:
    Reply
    • Qasim,

      Our current understanding of science is that it is not possible for one parent to be AB and his or her child to be O.

      It is not unusual for one party to have a different blood type than thought. It is wise to have all blood types retested before jumping to any conclusions.

      Best,
      @MsGreene

      Added:
      Reply
      • Anonymous

        Hi Cheryl Greene, my dad was AB+ and my sister is O- … test were done years ago and he is definitely her father …

        Added:
        Reply
  223. Jillian

    Thank you for this post!! I really enjoyed reading it! My mom is A- and my father is O+. I ended up O-and RH+. My mother is RH- and my father is RH+. Is there a possibility for me to pass on RH- as an active or recessive gene to my 3 daughters?

    Added:
    Reply
    • Stephanie

      Hello, I just found out that one of my daughters is RH+ and I’m O+. Can her father be any blood type?

      Added:
      Reply
      • Stephanie,

        You haven’t provided enough information to be able to provide a meaning full answer, but I can say that if you are Rh+, you can pass down the D antigen, and your child could be Rh+ even if her father was Rh-.

        Do you know your blood type?

        @MsGreene

        Added:
        Reply
        • Stephanie

          Yes, I indicated that I am O+ and my daughter is RH+. My question was if her father could be any blood type? I don’t know her father’s blood type.

          Added:
          Reply
          • Hi Stephanie,

            Sorry, I meant, “do you know HER blood type?” If you know her blood type, I can tell you the possibilities for her father, but without that, I can not.

            Best,
            @MsGreene
            Co-founder & Executive Producer DrGreene.com

            Added:
        • Stephanie

          Dr. Greene, I did say what HER my daughter’s blood type is… RH+

          Added:
          Reply
          • Stephanie,

            There are two part to the name of the type, the first is identified by A, B or O. The second is identified by + or – and is referred to as Rh+ or Rh-. But without the letter, that’s an incomplete type. Your type is O and is Rh+. You know that hers is Rh+, but is it A+, B+, O+ or AB+?

            Dr. Greene explains both in Blood Types 101: An Introduction to ABO Blood Types and the Rh System.

            Sorry we’re having trouble communicating about this one.

            @MsGreene

            Added:
  224. Sapphire

    My mom is O positive, my dad is A positive. My brother and sister are both O positive. Im O negative. Just wanna ask if it’s possible? Thanks.

    Added:
    Reply
    • Sapphire,

      Yes, it’s possible for one parent to be O+, the other parent to be A+ and their children to be O+ or O-.

      If you’d like an explanation, let me know.

      @MsGreene

      Added:
      Reply
  225. Manoj rana

    I have a O+ blood type. My parents are B+ (mother) and B- (Father). Is this outcome possible?

    Added:
    Reply
    • Hi Manoj,

      Yes, it is possible for one parent to be B+ and the other B- and their child to be O+.

      If you’d like an explanation, let me know.

      @MsGreene

      Added:
      Reply
  226. Manoj

    I have a B- blood type. My parents are O+ (mother) and B+ (Father). Is this outcome possible?

    Added:
    Reply
    • Manoj,

      Yes, it is possible for a child to have B- blood if one parent is O+ and the other is B+.

      Best,
      @MsGreene

      Added:
      Reply
  227. Helen

    Hi Dr Greene,My sister is o+ and the husband is b+ ,then there son is o- ..is it possible. Thsnks

    Added:
    Reply
    • Helen,

      Yes, it is possible for a child to be O- if his or her parents are O+ and B+.

      If you’d like an explanation, let me know.

      @MsGreene

      Added:
      Reply
  228. toya

    Hi good day
    I’m B+ and my husband is O+ and my son A+ blood is this possible…
    my son looks like both of us so its confusing
    and now his parents are questioning if thats there grand son

    Added:
    Reply
    • Toya,

      Our understanding of the current science is a B+ parent and an O+ parent can not have an A+ child.

      There is a good chance one of you has a different blood type than you think. Retesting is the next step.

      If that is inconclusive, DNA paternity testing is 99.999% accurate.

      Best,
      @MsGreene

      Added:
      Reply
  229. Lynne

    Hi there,

    My mother is A+ and my father AB+, and I am A-

    Is this possible? ?

    Added:
    Reply
    • Lynne,

      Yes, if one parent is A+ and the other is AB+ it is possible for their child to be A-.

      Let me know if you’d like an explanation.

      @MsGreene

      Added:
      Reply
  230. Alison McGinn

    Hi Dr Greene, My mothers’s blood group was A & my blood group is Rh A negative. I don’t know my father but what do you think his blood group would have been?
    Thank you

    Added:
    Reply
    • Hi Alison,

      If one parent has type A blood and his or her child has type A- blood the other parent could be A+, A-, B+, B-, O+, O-, but not AB+ or AB-.

      I hope that’s helpful.
      @MsGreene

      Added:
      Reply
  231. Aman

    hello Dr Greene, my both parents are B+ and we children have O+ AB+ and AB- is it possible or we were exchanged in hospital

    Added:
    Reply
    • Hello Aman,

      If two parents are B+, they can have children who are O+, but not AB+ or AB-.

      You might have been exchanged at the hospital or perhaps one of your parent’s blood types is different than he or she thinks it is. This is not uncommon. Perhaps the test was in error or recorded in error. For instance if one parent was B+ and the other was A+ or A-, they could have children who are O+, AB+ and AB-.

      I hope that’s helpful.
      @MsGreene

      Added:
      Reply
  232. Emma Morrison

    Hi my mum is Ab- and my dad is Ab+ but I am O+.
    Am I right in thinking that is not possible.

    Added:
    Reply
    • Emma,

      Our current understanding of science is if one parent is AB- and the other is AB+ they can not have a child who is O+.

      Sounds like the next step is retesting or discussing with your parents.

      Best,
      @MsGreene

      Added:
      Reply
  233. Winter

    Hello Dr. Greene.. I was rather confused about my blood type.. My father is O+ and my mother is B+ and all my brothers and sisters are B+ like my mother.. how can I have B- ??

    Added:
    Reply
  234. Lacey

    How do I figure out if me and my parents have the same blood type

    Added:
    Reply
    • Lacey,

      All three people need to have their blood tested.

      Best,
      @MsGreene

      Added:
      Reply
  235. Chase

    My dad is o+ and my mom is a+ and I am a- is that possible

    Added:
    Reply
    • Chase,

      Yes, it is possible for a child to have A- blood if his parents are O+ and A+. If you’d like further explanation, let me know.

      Best,
      @MsGreene

      Added:
      Reply
  236. Ammu George

    Hello Dr Greene,
    My mum is O- , my dad is B+, and my older sister is O-. However I am B-, is this possible, are they my biological parents? Please clarify this for me. :)
    Many Thanks

    Added:
    Reply
  237. Angie

    Hello, my question is this my son is O negative and his ex girlfriend is also O negative . She recently gave birth to a O positive baby girl and refuses a dna test but i have been under the assumption that two O negative RH negative parents can not make a positive child.

    Added:
    Reply
    • Hi Angie,

      Our current understanding of science is that it is not possible for two O- parents to have a child who is O+.

      DNA paternity tests are 99.999% accurate.

      Best,
      @MsGreene

      Added:
      Reply
      • Angie

        Thank you that was my understanding also.

        Added:
        Reply
  238. steph

    Can an a+ mother and an a- father conceive an o rhesus negative blood group child

    Added:
    Reply
    • Hi Steph,

      Yes it is possible for an A+ mother and an A- father to have an O- child. If you’d like an explanation, let me know.

      Best,
      @MsGreene

      Added:
      Reply
      • steph

        Hi i got it wrong my mum is a- and my father is a+ blood group is it possible for me to be o rhesus negative

        Added:
        Reply
        • Hi Steph,

          Yes, it is possible for a child to be O- if his or her parents are A- and A+.

          If you’d like an explanation, let me know.

          Best,
          @MsGreene

          Added:
          Reply
      • Ali

        Dear. If motherb is A + and baby is AB -. What possible groups father may have

        Added:
        Reply
        • Ali,

          If the mother is A+ and the child is AB- the father is either B+ or B-.

          If you’d like an explanation, let me know.

          Best,
          @MsGreene

          Added:
          Reply
  239. Ammu

    Hello, I am only 13 and would like to know more about all of this bit, i cant seem to understand everything that has been written, if it is possible could you translate it inot simpler terms.
    Thank you
    Ammu

    Added:
    Reply
    • Ammu,

      Each person has two alleles that make up a blood type.

      The most common alleles are labeled A, B and O.

      Each parent passes one allele down to his or her child, so the child’s blood type is determined by the type passed down from both parents.

      Does that help?
      @MsGreene

      Added:
      Reply
      • Ammu George

        Thank you Dr Greene! That’s really helpful, that will really help me in my upcoming exams!
        Once again thank you very much!
        Ammu

        Added:
        Reply
  240. gittik

    Hi my blood group is a- and my mother blood group is a+ and my father is b+ its possible.

    Added:
    Reply
    • Gittik,

      Yes, this is a possible combination.

      If you’d like an explanation, let me know.

      Best,
      @MsGreene

      Added:
      Reply
      • Karon McMakin

        I’d like to have the explanation of how an A+ and B+ have a child with A- blood. That’s my situation and we’ve always been curious!

        Added:
        Reply
        • Hi Karon,

          Blood types are comprised of two alleles. The common alleles are A, B, and O. These combine to make up blood type A, B, O and AB.
          – If someone is A, he or she can have two A alleles (AA) or one A and one O (AO).
          – If someone is B, he or she can have two B alleles (BB) or one B and one O (BO).
          – If someone is O, he or she can only have two O (OO).
          – If someone is AB, he or she has one A and one B (AB).

          Likewise, the Rh system is comprised of two alleles. Positive (+) and negative (-).
          – If someone is Rh+, he or she can have two positives (++) or one positive and one negative (+-).
          – If someone is Rh-, he or she can only have two negatives (- -).

          Each parent passes down one allele for blood type and one for Rh. In the example you give:
          – The parent with type A blood passed down an A.
          – The parent with type B blood passed down an O.
          – Each parent passed down a negative allele.
          – The child would be type AO, Rh- or A-.

          Hope that helps,
          @MsGreene

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  241. Tyler

    My father is AB+ and my mother is o+ my blood type is o- is that possible?

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    • Tyler,

      Our current understanding of science is that it is not possible for one parent to be AB+, the other to be O+ and their child to be O-.

      Before you jump to any conclusions, it’s wise to talk to your mother about having everyone tested again. It’s not uncommon for one of the types to be different than what people think it is.

      Best,
      @MsGreene

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  242. Our current understanding of science says it is not possible for two parents with Rh- blood to have a child with Rh+ blood (though two parent’s with Rh+ blood can have a child with Rh- blood). Dr. Greene explains how and why in this Q&A Blood Types 102: The Role of A, B, O, and AB Groups In Determining Paternity.

    Before you jump to any conclusions though, keep in mind that it is not uncommon for one of the three blood types to be different than what is thought. This can happen because a test is in error or it is recorded incorrectly.

    If, after checking for accurate blood types, you are still concerned, it is possible to have an at home DNA Paternity test. You can even order these online. Some are valid for legal purposes and others are less expensive, but not used for legal purposes. Both tests claim to be 99.999% accurate.

    As Dr. Greene says, “I realize that the circumstances that prompt a person to undergo paternity testing are often difficult. I hope that whatever you want turns out to be true. Even more, I hope that whatever turns out to be true becomes something that you learn to want.”

    Best,
    @MsGreene

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  243. Mandy

    My Mother is A+ and my Father is o+. I am A-. Is this possible ?

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    • Hi Mandy,

      If one parent is A+ and the other is O+, is it possible for their child to be A-. No problem at all.

      If you’d like an explanation, let me know.

      Best,
      @MsGreene

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  244. Mara

    I have always had my suspicion that my “birthparents” arent actually by birthparents. I grew up in the foater ayatem and upon research found out my parents blood. My father according to his bloodcard is an A- while my mother according to her bloodcard is O-. I am a B+. I also do not share resemblance to either parent.
    We have all been tested by bloodsource and given cards for medical purposes. How is this possible?

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  245. Lisa

    My Mom is O+
    My Dad is O+
    Both my siblings are O+
    I’m A+
    Is this possible?

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    • Lisa,

      Our current understanding of science is that two O+ parents can only have O+ or O- children.

      It is not uncommon for one or more of the individuals in question to have a different blood type than they think they have. This can be because the test is in error or it was recorded incorrectly. It’s wise to talk to your mother about retesting before jumping to any conclusions.

      Best,
      @MsGreene

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  246. Jo

    I am O negative and my husband O positive . But we have child of B + .. Is that possible?

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    • Hi Jo,

      According to our understanding of the current science, this is not a possible combination. There are two reasons for this outcome:
      1) One of the blood types is not what you think it is.
      2) The person you think is the father of this child, is not.

      If you’re sure your husband is the father, it’s time to get everyone’s blood type retested.

      Best,
      @MsGreene

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  247. Lori

    hi , My mother is A positive and my father is O positive but I am AB positive. how is this possible. I am too confused

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    • Lori,

      Our understanding of the current science is that a parent who is A+ and a parent who is O+ can not have a child who is AB+.

      Before you allow your confusion to become an accusation, it’s wise to have all three party’s blood retested. It’s not uncommon for one of the three types to be different than what people think it is.

      I hope that helps,
      @MsGreene

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  248. D Green

    I’m not sure on my parents blood types but I’m A+ and my sister is A-. It’s this any indication that we may not be full sisters?

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    • D,

      It is very common for two siblings to have different Rh factors. It is not an indication that you may not be full siblings.

      @MsGreene

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  249. Alexis

    Hi, I am wondering of both of my parents are a+ ,can they have a child who is o-?

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    • Yes, it is possible for two A+ parents to have an O- child. If you’d like an explanation, let me know.

      Best,
      @MsGreene

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  250. Dexie

    Hi. If my husband and I are both O blood type, is it possible to have a child with A blood type? is it possible to get the child’s blood type on grandparents?

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    • Dexie,

      Our current understanding of science is that it is not possible for two O blood type parents to have a child with A blood type.

      Some times children have different blood types than their parents and the same blood type as grandparents, for instance two type A or two Type B parents can have type O children. Here’s why:
      A is dominant
      B is dominant
      O is recessive

      Blood types are comprised of two alleles:
      Type A = AA or AO
      Type B = BB or BO
      Type O = OO

      This means:
      Type O (which is made of two Os) can only pass down O
      Type A can pass down A or O
      Type B can pass down B or O

      Hope this is helpful,
      @MsGreene

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  251. kim

    hello,
    my mother is O+ and my father is B+ .can they give birth to a AB-

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    • Kim,

      Our current understanding of science is it would NOT be possible for an O+ parent and a B+ parent to have an AB- or AB+ child.

      If you’re interested in the reasoning behind this let me know.

      In the meantime, remember blood type tests can be in error or reported in error. It’s wise to retest both parents and child before making any judgements.

      After testing, if further information is needed, a DNA paternity test is a good option. It offers much more information than blood type alone.

      Best,
      @MsGreene

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  252. Deborah

    Please help if you can concerning the rh A negative mother and Rhode An positive father. My father loved me very much but my mother did not. She loved my sister who was 12 years older. It would not upset me at all if she weren’t my biological mother. Please help if you can. When my blood was typed and it came back O positive the doctor told me it was impossible due to my parents blood type. Are the doctors correct.
    Thank you for your home help.
    Deborah

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    • I am unfamiliar with “Rhode An positive” blood type. Might this be a typo? If so, please correct.

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    • Valerie

      Can a 0+ and b- be full siblings ?

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      • Yes, this is possible.

        If at least one parent is type B and the other is not type AB.

        Best,
        @MsGreene

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  253. Deborah

    Hello,
    Please help. My mother was rh A negative and my father was rh Ab positive. My sister was rh Negative and even though she had the prenatal injections for rh Negative, she had 4 miscarriages. I have O positive blood. How is this possible ? Could I possibly have O positive blood from these parents? I am 60 yrs of age and there has always been a possible discrepancy in the family. Please help if you can.
    Thank you

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    • Deborah,

      Our current understanding of science is that a person with AB blood type can not have a child who is type O. The reason is all people with type O blood have an O from each parent and someone with AB blood type does not have an O to pass down.

      We always remind folks that blood type test results can be in error or can be recorded and passed down in error. It’s wise to retest when possible. It sounds like that may not be an option for you.

      If there is a discrepancy, might it be that you were a very wanted child, but your parents were never comfortable discussing this with you?

      Hope this helps,
      @MsGreene
      Co-founder & Executive Producer, DrGreene.com

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      • Deborah

        Thank you so much. Is it possible my father could have the rh An positive and my real mother was an O positive? My father loved me very much but unfortunately my mother did not feel the same. You have answered a lifetime of question. Bless you for your help.

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  254. Ara

    My father is O blood type while my mother is AB blood type and ihv learned in school that its impossible for AB and O to have O or AB for their kids but two of my brothers have O blood type? I’m so confused. Is this possible?

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    • It is not considered possible for one parent to have AB blood type and the other to have O blood type to have children who are either AB or O.

      We know our understanding of science is constantly growing, so we may find our current understanding is wrong. It is also possible that one or more tests are in error or were recorded in error.

      Before jumping to any conclusions, it is wise to have everyone’s blood tested again. If there is still a question, DNA paternity testing is much more sensitive than blood type testing.

      Best,
      @MsGreene

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  255. Latona

    I’m A positive my daughter is B positive (so I was told when she was 4 days old) what would father blood type be.

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    • If one parent is A+ and the child is B+, the other parent could be either B+ or B-.

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  256. Snowflakes

    I am type AB from our blood typing in school but my mother is type B and my father is type O. I got some of my mother’s features and as well as some features from my father’s side but still, because of the result of our blood typing in school I started to feel curious and I want to find the truth by myself. I hope you could help me THANKS ??

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    • It sounds like you have information about how blood types are inherited. Whenever there is a discrepancy, I encourage retesting of both parents and the child. It’s not uncommon for one of the three results to be in error or to have been recorded in error.

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  257. Daniel Ssemambo

    I am B- and would like to know if possible to have a DNA test carried out on my children and what can prove they are mine?

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    • DNA paternity testing is now easily avaiable.

      Here is a link to an option for Paternity Testing. They offer a home test for under $200. This can’t be used for legal purposes, but can give you paternity information.

      If you need to determine paternity for legal reasons, the price is higher (around $450) and you have to go to their location.

      We are not connected in any way to this lab. There may be others that offer more affordable options or have labs closer to you. Before you decide to do paternity testing, you may want to look online for other options.

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  258. bill

    you are nothing more than a commie if you have to censor my question. you must belong to the media slugs. I HAD ASKED YOU NICELY …YOU SHOULD DELETE THIS SITE .

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  259. STBAT

    I am the daughter of a mother who is O+ and a father who is AB-. Upon going through nursing school I was told this is not possible. My father was in the military and his blood type is on his dog tags. I am sure he was typed correctly. My Anatomy and Physiology teacher saw my type along with the doctor from my five pregnancies. They all typed me as O-. I have read that on rare occasions that AB parents can have an O child. Can you please explain this better to me?

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    • karan

      IT is possible to have O-ve just read the article. since your parents have such diverse blood group it is possible for you , too have any blood group based on the combinations possible, since your mom could be O positive having the (+ -) rh factor, so you could be O+ or –

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    • Brooke

      Hello, I have the same predicament. My father is now deceased, but he told me before dying a few years ago that he had the “weird, rare type” that I do, which is AB neg. My mother swears up and down that she is O pos. There is an extremely rare type of AB that is inherited solely thru paternal lineage, but I am not sure of the exact name…it’s on the tip of my tongue, tho. Please email me if you find that this is the case with you, as only a handful of us are thought to exist, and I have found that I have very special connections with others of our type to a point of not minding contact from a veritable stranger…I know it’s fine.

      Best,
      Brooke

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      • Brooke,

        The type you are looking for may be Bombay, which is hh, but is reported as O because the blood tested for ABO blood type can not record hh.

        If you think this is the case, talk to your doctor about a specialized test for this blood type as it does not show up using the normal ABO blood type tests.

        I hope that helps.
        Best, @MsGreene
        Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

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  260. Charles

    Is it possible for two Os to make an A baby?

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    • Based on our current science, that is not considered possible. What is possible, is for one of the three blood types to be taken in error, reported incorrectly, or remembered differently than was reported.

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  261. Gene

    My dad is O blood group and my mother is B. Mine is A. Is it possible or can it be that my dad isn’t my real dad?

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    • Based on our current science, that is not considered possible. What is possible, is for one of the three blood test to be in error, reported incorrectly, or remembered differently than was reported.

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  262. T'Anna Morris

    I just had a baby about 2weeks ago and I found out my son is b postitive so is his father but the father’s parent’s are both o negative , I am o postive blood what blood type does it make it to a b postitive.

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  263. Punam Khandagale

    My blood group is B (-) ve my wife’s blood group is O (+) ve, but my daughters blood gruop is B + ve,
    can it be possible?

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    • Punam,

      It is possible for one parent to be B- and and the other parent to be O+ and their child to be B+.

      The possible children from one parent who is B- and the other parent who is be O+ are:
      — O+
      — O-
      — B+
      — B-

      I hope this is helpful.

      @MsGreene

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  264. Sheila

    My dad is O+AND I’M B- WHAT BLOOD TYPE WOULD MY MOTHER BE. OR IS MY DAD TRULY MY DAD

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  265. MK

    Recently I have found out that my blood type is A negative and it’s rare but my fathers blood type was O, both parents have given me different versions of how I was born and I am starting to suspect that something doesn’t add up. My mother has passed now and I don’t know her blood type, and I don’t know how to obtain this information as I come up against a brick wall, where would I go to find out about my mothers blood type and where do you go to, to get a DNA as it’s very unsettling to me to find out that two parents are not telling me the truth about my birth. My mother tells me I was born breach and she didn’t see me for 10 days after the birth, she didn’t know if I was alive or dead I found it very strange that she would leave it 10 days and didn’t ask a nurse how her baby was because she said there were at least 14 doctors at my birth because I was a breach birth and their had been difficulties. My father on the other hand told me he picked my mother and I up from the hospital four days after my birth and I was not born breach, where can I go from here!! very confused.

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  266. Kara

    I don’t know my mothers blood type, but my father was RH negative. Could I be RH negative too?

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  267. Tammy

    Can a father b positive and a mother a positive have a ab negative child? Or can a father b positive and a mother a negative have a ab negative child?

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    • Tammy,

      In his article Blood Types 101: An Introduction to ABO Blood Types and the Rh System Dr. Greene explains how this is possible. Here is an excerpt from that article:

      In this system the positive are dominant over the negative. Thus if your genetic type is ++ or +-, your blood type will be Rh positive. Only if your genetic type is — will you be Rh negative. This means that if both parents have Rh+ blood with the +- genes, they could have children who are ++, +-, or – -. In other words, their children could be either Rh positive or Rh negative. Children who are Rh negative can have parents who are either Rh positive or Rh negative.

      This is why two parents who have O positive blood could easily have a child who is O negative. In fact, most children who are O negative have parents who are positive, since the +- combination is so much more common than the – – combination.

      I hope that’s helpful,
      @MsGreene

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  268. Noosha

    Hi my parents they both have O+ blood and mine is B+. How is it possible?

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    • hassan

      Hi my parents they both have O+ blood and mine is B+. How is it possible?

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      • Jacob

        Current scientific studies examine that two O + parents cannot have a B+ child. Parents with O+ can only yield children with O blood types, positive or negative. In order for a child to yield B type one parent must be B type. It’s likely that the information was erroneous. Suggestions would be to to reexamine all parties blood types.

        – Jake

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  269. Jeeva

    Is it possible for a child to have o negative blood group if parents have b positive and o positive blood group

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  270. DeBorah

    Is it possible for two A++ parents have an 0–baby?

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  271. jai

    Is it possible for a child to have a b- blood group with parents having o+ & A+ group?

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  272. shani woolford mclaughlin

    Hi there im AB Rhesus Neg blood group and my mum is A Rhesus Neg what would be my fathers type plz x

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    • Hello Shani,

      If one parent is A- and the child is AB- the other parent can be B-, B+, AB- or AB+.

      Hope that helps,
      @MsGreene

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  273. Mizz Mek

    I am AB- (although for some reason I turn up B- on some tests – this is what I am truly interested in understanding although the discrepancy of my parents blood type tested and retested – makes my birth and bloodtype a supposed impossibility) please note: both my parents are O+
    We have tested and they are both my parents. (Not just one time, but several times, as everyone scratches their head in confusion). We even went as far as to test sibling uncles and aunts – with no luck in finding an answer to impossibility.
    I have had no transfusions and both my parents have not had blood transfusions.

    My question is not so much to the impossibility of me being born an rh negative, but the potential changing of the AB to B negative at various tests. We’re talking I’m almost 50 – and I’ve given birth to a daughter with Rhogam, etc.

    I don’t think the testing points are making mistakes, so wondering if there is something unusual about me – maybe food I eat or otherwise, that can be causing this variance? Hormones? Anything? I’m a single child to my mother and father so no siblings to this bloodline.

    My ex is an O+ and I believe my daughter – at last count – was A+.

    Thanks – I don’t want to seem like and idiot, or that I’m lying – because with all the strange reactions I’ve gotten, I realize this is an anomaly. However, it is what it is, and I’m wondering if perhaps it’s that the tests are not sensitive enough… or there is some sort of antigen blocking agent that causes it – or if maybe I have too much iron or something in my blood that it is causing this reaction.?

    I’ve always just assumed that someone screwed up somewhere. But we’re talking at least 15 tests = 3 pregnancies – where I lost what I assume was + factor child. I almost lost my daughter at 3 and a half months -and had multiple shots of rhogam – and well there is a long story after that – had to go on bed rest last month.. and I felt sicker than snot.

    But anyhow – I’m curious about all of the potential possibilities for my blood type to sometimes come out B- and sometimes as AB-…. And while my mom and dad are both o+ they are definitely my actual parents.

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    • Dear Mizz,

      I’ve said on this board multiple times, our science is limited. We know what we know, but we have no idea what we will learn in the future. Who knows, we may find a specific type that changes in certain situations, such as pregnancy.

      Have you presented your case to a geneticist at a major research hospital or university, such as Stanford or Harvard? You may be of interest to their studies and they may be able to help you find answers.

      Best,
      @MsGreene

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    • Sarah

      If you haven’t already tried it, buy a blood type test kit and try taking the test yourself and see what results you get.

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  274. Joseline

    DR.GREENE,
    My mum blood type is A+ and my dad is o+ but i am A- how possible is it please .
    Please help to me understand

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  275. SM

    My mom Isaid a b+ and my dad is a b+. But I’m an A- blood. Is that possible? My Dr told me that my dad can’t be my dad because of my blood to get dna. Test

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    • Dear SM,

      In cases like the one you described, it’s wise to have everyone retested before jumping to any conclusions. It’s very possible for one of the three types to be different than what you think it is.

      If the re-tested results come back the same, a DNA test can tell you if the man you call dad is indeed your biological father.

      I hope that helps,
      @MsGreene

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  276. Mousey

    I am O neg; my husband and father of our children is O pos. First born is A+. I’m told this is impossible, but there is no other answer: no affairs or other person could be father???

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  277. sanjay

    Hello My wife blood group is O-ve and my Blood group is O+ve and my daughter’s blood group is O-ve.

    Is it possible? .

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    • Sanjay,

      Yes, this is a possible outcome. But you need to be aware of the risks associated with subsequent pregnancies.

      Please see Dr. Greene’s Q&A How To Determine and Manage Rh Incompatibility. He explains that the first pregnancy is not an issue, but if not properly treated, it can be an issue.

      I hope that’s helpful,
      @MsGreene

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  278. Yvette

    Hi my sister and I were born in the 1950’s. My mum was O negative my dad was O positive. Both us sisters are O positive. Mum was sensitised on first pregnancy and my sister was born heavily jaundiced. Second pregnancy was no problem, with me being delivered as a home birth. Is this possible as I assumed the antibodies in my mums blood would have attacked me?

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    • Yvette

      I realised i have not explained things so good. To clarify, my mum only had two children, me and my sister. Both of us were O positive. My sister suffered jaundice at birth as my mum had become sensitised at some stage but I suffered no ill effects from antibodies, even though my blood would not have been compatible with my mums O negative type blood. Thanks, Yvette

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      • Yvette

        Hi and thank you for responding but I think you have misunderstood. My mother was sensitised during her first pregnancy and as a result my sister was born heavily jaundiced. As this was the 1950s there was no treatment and so when my mum got pregnant with me, another O positive baby I thought the antibodies should have attacked me but they did not.

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  279. Lydia

    HELLO,
    When I found out I’m A+ I questioned my mother her blood type is O+ and my so called father is O-. My brother and sister are O’s. We keep questioning her but denies someone else is my father. I need answers been trying find out for 15 years. Please help ?

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    • Have you had your blood types re-tested? I know that’s an obvious question, but, in a scenario like this, it’s not unusual to find someone’s type is different than he or she thinks it is.

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  280. Samantha

    Can 2 A positive parents make a O negative child? Can someone please help me understand.

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  281. Sass

    Can I be a B Rhesus Negative and my Siblings be an O positive. My mum said she was A+ . I could potentially be my step father’s child? By as my father, step father and mother have passed away there is no way of checking their blood group. What are the % probabilities do you think?

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    • Hi Sass,

      Blood types are made up of two alleles. One comes from each parent.

      Here’s how that can look:
      — O = OO
      — A = AA or AO
      — B = BB or BO
      — AB = AB

      Here is one scenario that would explain what you’ve outlined:

      — Mum = AO
      — Dad = BO
      — Child 1 gets an O from Mum and a B from Dad
      — Siblings get O form Mum and O from Dad

      Additionally, if Dad were Rh-, each of his children would have a 25% chance of being Rh-.

      Basically, what you’ve outlined is possible.

      Hope that helps,
      @MsGreene

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  282. Eric

    Hi. My father lives in spain he wanted me to come live with him there. During the process of the paper work, a DNA test had to be done to prove if truely am the real son of my father which they took some tissues from my mouth . just yesterday the results came out and my DNA matched totally different from my father’s. I had a talk with my mom to know whether she had an affair with another man whiles she was with my father. She was clear to me that such thing never happened and I believed she was telling me the truth. I also believe my father is my real father because, there are a lot of resemblance between me and my father’s mother that is my grandmother but the DNA test proves the man I believe is my father is not. Please can there be any possibility that such thing can happen. I really need a quick reply because we have only one month to appeal to the Spanish embassy.

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  283. Jalaj Gupta

    My parents have B+ blood group. And my blood group is A-.
    Is it possible that am adopted?

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  284. Kim Smith

    My mother has O negative blood. she does not know either of her parents blood types. What are the possible type and rh factor combinations?
    If it helps, I am B positive and my father is B positive. I am the second child of my mother and father, my 3 younger siblings (same father) are all O negative. My mothers first child was adopted out (different father)and do not know blood type.

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  285. Thea Weiss

    Years ago when I was in my 20’s (I’m 61!), I accused my parents of adopting me because I am AB- and my Dad is O. He knew because of blood typing in the army in WWII. I knew because in my high school biology class we were allowed to test for our blood types. I was, at the time, a lab tech at Downstate Medical Center in Brooklyn, NY. I was sure my parents had lied to me, and was very upset. They were, of course, angry when I confronted them about it. Afterwards, a biochemist told me that there is actually a 1 in 10,000 chance of a mutation in the proteins on the blood cell surfaces that can make it possible for an O parent to have an AB child. What is the science (reference?) behind this? Thanks, from “a Mutant” (I think)!

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    • Jan C

      Both my parents have O blood andso does my siblings, I’m the only one with B+ blood type. However my question is there anyway the man I call my father.. My father???

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      • Akeeme Emanuel

        Hi if it helps my self and my baby mother is o positive and my son is B

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    • Sarah Wheeler

      Wow, just like me. I wanted to know how and why it’s possible that my (Dad is O+) Mom is AB+ and I am O+. It says everywhere I’ve looked that it is impossible. And I’m confused.

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    • Legendary

      I was wondering same but not negative positive could I have AB+ if my dad has O+

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  286. Cassidy S.

    My husband is A-, his ex-wife is O- and had to have the RhoGam shot. Their daughter is A+, their son is A- like my husband and the two children he had with me(even though I’m O+). His daughter is 23 and finally decided she wanted to know the truth, so my husband and she did a DNA test. It came back that my husband is 99.95% his daughter’s father. How is their daughter A+ blood type when both her parents are RH-?

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  287. Marilyn

    We adopted “twins”. Our daughter has B- and our son has A+

    Doesn’t matter to us, but is this even possible? What blood type might the biological parents have been?

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    • Hi Marilyn,

      Yes, this is possible. Since one twin is male and the other is female, they must be fraternal twins, not identical. This means, they have the same “rules” for blood types as other siblings.

      One possible combination that would result in one child being A+ and the other B- is one parent being AB+ and the other being AB-. In this case each child would have a 25% chance of having type A blood and a 25% chance of having type B blood (the remaining 50% would be AB). Each child would have a 75% chance of being Rh+ and a 25% chance of being Rh-.

      Hope that’s helpful or at least interesting.

      Best,
      @MsGreene

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  288. Carla

    Thanks for clearing up this long overdue answer to my question.

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  289. Patsy

    If a mother is O reh neg and father is O poss can you have an O reh neg child ?

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    • If one parent is O- and the other is O+ there is a 100% chance each of their children will be blood group O and a 6.25% chance each of their children will be Rh-.

      Please note that if a mother is Rh- and her partner is Rh+ there may be complications for pregnancies after the first one. Dr. Greene has written about that in this How To Determine and Manage Rh Incompatibility.

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  290. Tessa

    I’m having the same issue I’m o- they said hubby was ab+ and my first born b+ I want to say my second was the same but she could have been ab and I know he’s there father but it keeps saying impossible when I looked into it did they get something wrong

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    • Tracey

      … There is a 50% chance of having a child with B+ blood, if the parents are O- and AB+.

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      • This is correct.

        Type A and B are dominant and O is recessive.

        — If one parent is type O, that parent has two O alleles.
        — If the other parent is AB, that parent has one A allele and one B allele.

        Each parent contributes one allele to each child. In the above scenario,

        — Parent one will always contribute an O allele.
        — Parent two will contribute an A or a B allele.
        — So each of their children have a 50% chance of being AO, which is type A blood, and a 50% chance of being BO, which is type B.

        Hope this helps,
        @MsGreene

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  291. Marie

    Hi I’m a O+ blood group but the hospital said my daughter is AB how has that happen my partner doesn’t know his blood group but the charts say that it’s impossible for me to be her mother I know she my baby as she was born with a disability not something that could be swapped at birth. Our son is a O+ like me. When I question the nurse about her blood group she just said dad must be A or B.

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    • I’m guessing there is an error in her blood type. I’d ask to have it retested.

      @MsGreene

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  292. Kaitlyn Anson

    Hi, so my Mom is o+ and my Dad is A- and my blood is A-, and I’m the third child in my family, was I at risk of having the Rh factor when I was born, because I had nothing wrong with me when I was born.

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  293. Angela

    Hello there,
    My mother is Rh- and my father is O+ what would the out come be if it was my blood type

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    • Hi Angela,

      If one parent is Rh- and the other is Rh+, the child can be either + or -. Each child has a 75% chance of being Rh+ and a 25% chance of being Rh-.

      The blood group is determined by the blood group of each parent. Since you didn’t provide the blood group of your mother (A, B, O or AB) I can’t tell you what blood group you might be.

      Sorry I can’t be more helpful.
      @MsGreene

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  294. Sue

    Hi, my mother had rh neg blood and my father was b positive and i am o positive …….is this possible , i;m confused

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  295. mary hogencamp

    hi
    my mother has O+ an the one she says is my real father has B+ but i got A+ and my son took after me with A+ i was wondering if this was possible or could of been switched or adopted because the one thats suppose to be my full blooded brother has B+ and my half sister has O+ i seem to be the only one that has A+ blood type

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  296. Danielle

    If I am O- does that mean both of my parents are positive?

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  297. Sumanth

    I am B+and my wife is O+. we had a son of A+. How is this possible. Whether i am not his father?

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  298. Sarah

    My dad told me when I was 23 that he was NOT my biological father. He was drunk at the time…and says a lot of questionable things. My mother disputes this and says he is my father. But…as it turns out, everyone in my family has type AB positive blood type. I have O positive. Here is my question…could he have told me the truth? Is it possible for two AB positive parents with other children who are also AB positive to have an O positive child?

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    • Sarah,

      Our best science tells us two AB parents can only have A, B or AB children. The reason is each parent contribute one allele from their blood type to each child. AB parents can only contribute A or B.

      If this is important to you, DNA testing is the next step.

      I hope this is helpful.
      @MsGreene
      Co-founder and Executive Producer, DrGreene.com

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    • Michelle Heatherly

      He was telling u the truth it’s impossible

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  299. Misty

    Both of my parents are O positive blood types as well as my brother and sister and my blood type is A negative I visited a doctor and he told me that it was very rare for two positives to have a negative and the fact that I don’t have O blood type at all is what throws me off but my mother said my grandma on my father’s side has A negative blood would that factor in? I love my father with all my heart and he has been a wonderful father and I would hate to find out any different but on the other hand if I have some family out there that I don’t know about I would also like to know that. So I could possibly feel like I fit in somewhere my brother and my sister are nothing like me at all.

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    • Hi Misty,

      If two parents have Rh+ blood, there is a 6.25% chance that each of their children will have Rh- blood. Rare is a relative thing (pun intended), but seriously, when we say something is rare it means it doesn’t occur often, but not that it doesn’t happen.

      On the other hand, our best science says two parents with type O blood can only have children with type O blood. This does not mean the wonderful man you know as your father is not your father. It is not uncommon for blood types to be in error either from the lab or due to reporting or one of the three parties is remembering it differently than it is. I highly recommend discussing this with your mom and, unless she has something she wants to tell you, asking for all your blood types to be retested.

      Hope that’s helpful,
      @MsGreene
      Co-founder and Executive Producer, DrGreene.com

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  300. golara

    Hi . I need donor for pregnancy. I have find some one who has ab blood group and myhusband has positive o .so the child might be b or a.
    my blood group is positive b .
    We wont decide to tell anybody about this. So is ther any exception that o blood group and b blood group generate a blood group because we have to explain if it will happen ?

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  301. Christine

    Hi my mother is Rh negative o and I am Rh negative o but my brother is not Rh negative o though I’m not sure what group he is , our father has passed away but he was not Rh negative o is it possible he is not my father x

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    • Unfortunately, there is not enough information from what you’ve provided to be able to tell you if he was your father or not. Here is what I can say — according to our best scientific knowledge at this time, if one parent is O- and the child is O-, the other parent is either A-, B- or O-.

      I hope that’s helpful,
      @MsGreene

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  302. Anne

    My father is A, my mother AB, I am O
    Also both have blue eyes, mine are hazel

    This seems improbable that I’m biologically related to both…yes?

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    • Hi Anne,

      Here’s a very simplified answer to your question. Blood types are made of two alleles, each with a letter name. The most common (by far) are A, B and O.

      Here is how we name blood types:
      — Type A = A & O or A & A
      — Type B = B & O or B & B
      — Type O = O & O
      — Type AB = A & B

      Each parent contributes one allele to their child’s blood type. Therefore, if one parent is A and one parent is AB, each of their children could be:
      — Type A –> A & A
      — Type A –> A & O
      — Type B –> B & O
      — Type AB –> A & B

      To be a Type O the child would have to get an O from each parent and the parent with AB does not have an O allele to contribute.

      A word of warning — it is not uncommon for blood types to be different from what you think they are. Either one of the tests was done incorrectly, or there was a reporting issue or someone’s memory is wrong. Before you jump to any conclusions, ask to have everyone’s blood re-typed. An open conversation about this is often the best course of action.

      I hope that helps,
      @MsGreene
      Co-founder & Executive Producer, DrGreene.com

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      • Anne

        Thank you. I tried to have a conversation but my mom flipped out….

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      • Confused

        I recently discovered my dad is o negative. My mom is B+. I am AB+. Am I crazy or is it genetically impossible for my dad to be my dad? I have been retested and so has my dad. We are certain of our blood types.

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        • Confused,

          According to our understanding of science at this time, an O+ parent can not have a child who is AB+. If you think you’d like to pursue this further, you can have DNA paternity testing done. It’s now around $200 and you can order it online.

          I hope that’s helpful.

          Best,
          @MsGreene

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    • Sarah Wheeler

      Hi Anne, my mother is AB+ also and I still turned out to be O+ we are so special haha^_^

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  303. Rona

    My blood type is AB, my mother is AB, and my father have O blood type is it possible that i’m adopted?

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  304. Katie

    My husband and his ex wife both have ab- blood type so does his son he had with her. He’s concerned it may not be his so is that possible or would his son have had a different blood type like a positive or just a or b? I’ve been told usually all three pepole don’t have the same blood type but, then I’ve been told it is possible so we were confused.

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    • Hi Katie,

      Each person has two alleles that make up his or her blood type. Here is how that looks:

      Type A blood = One A allele and one O allele or One A allele and one A allele
      Type B blood = One B allele and one O allele or One B allele and one B allele
      Type O blood = One O allele and one O allele
      Type AB blood = One A allele and one B allele

      Each parent passes down one allele, so the child has one allele from each parent.

      In the case of two parents being AB-, each of their children have a 50% chance of having an AB blood type, a 25% chance of having blood type A, and a 25% chance of having blood type B. 100% of their children will be Rh-.

      Blood types are not considered a valid paternity test. DNA testing is much more accurate.

      I hope this is helpful,
      @MsGreene
      Co-founder and Executive Producer, DrGreene.com

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      • Katie

        Helps a ton! Thank you so much!

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  305. Dimple

    I’m confused now. So my Mother is O + and Dad is O, as well. My Brother is also O… but I’m B +

    what the heck happened? Is that my father?

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    • If both parents are type O, that means they have two O alleles and can only pass along type O.

      If one parent is type O and one is type B, they could have children who are type O or type B.

      In your situation it is wise to have all parties blood type tested again before jumping to any conclusions. It is not unusual to find that one of the types was in error either from the lab, in reporting or in people’s memory.

      Hope that helps,
      @MsGreene

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      • Michelle

        My husband and I are both type O and our first daughter was type O, but our second daughter was type A ? Strangely we shared the same blood disorder, and she inherited other things from her father,also we both have direct relatives with type A blood. We were all tested again for blood type. She is our daughter and we were amazed at the odds of this happening but it did !

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        • Michelle,

          I am struck by how little we know sometimes. Science is continually growing and with it our understanding. I’d love to hear the specifics of your results and how your geneticists are explaining the rare outcome.

          Best,
          @MsGreene

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  306. Amir

    My wife A negative and I have B negative blood type. Is it possible for our children to be B positive?

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    • Hi Amir,

      That is not considered a possible outcome. It would be wise for you all to have your blood type tests run again. This is especially important if your blood type is actually Rh+ instead of Rh-. It will be important to know this before considering having another child.

      Best,
      @MsGreene

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  307. Ann

    Last year I just founed out that my blood type is B blood type
    And my mother is o postive and my dad believes that he’s o positive
    But when my doctures told me that I was B and not O positive my mum and dad were both puzzled is it possible that my dad might not be my dad
    Can I do a home DNA test to fined out ??

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    • Jones

      It means that your mom and dad blood type allele is carrying a B. Even your siblings are all type o positive, that chance of you being a type B is completely normal. Probably one of your grandparents is either type AB or B.

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  308. miriam

    My blood group is A positive and I have sisters with AB negative my mother blood group is O positive is it possible for me and my sister to have the same father and if not what will be my father blood group

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  309. Melissa

    I just had a baby last week.. I am A-, daddy is O- but the baby is B-?? Is that possible or am I going to have to start proving myself and setting up DNA tests for his already skeptical family. He was in the military and says he knows his blood type is O- for sure.

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  310. sabrina

    I’m b+ and my ex husband is a + but my son is a + but my daughter is o+ how did that happen cause I like to know please cause it’s got me worried

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