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

Are they really my parents?

Dr. Greene’s Answer:

Genetics can be so confusing! I can easily see how after much research the issue 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 the founder of DrGreene.com (cited by the AMA as “the pioneer physician Web site”), a practicing pediatrician, father of four, & author of Raising Baby Green & Feeding Baby Green. He appears frequently in the media including such venues as the The New York Times, the TODAY Show, Good Morning America, & the Dr. Oz Show.

  1. 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.

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    • Hi Anna,

      So sorry to hear about your miscarriages. I know that is heartbreaking.

      Blood types are comprised of two alleles for A, B and O (there other rare types, but are not necessary to address here). And two alleles for Rh+ or Rh-.

      People with type A+ can be AA or AO and Rh+ can be ++ or + -.

      People with type B+ blood can be BB or BO and can be ++ or +-.

      Each parent passes down one allele for blood type and one for Rh type.

      In this example, it would be possible for each parent to be AO+- or BO+- and for each parent to pass down the O and the Rh-. In that case their child would be OO–, which we call O-.

      I hope this information is some how helpful.

      Best,
      @MsGreene

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  2. 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

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    • 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

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  3. 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?

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    • Jillian,

      If a person is Rh+ he or she can have two + alleles or one + and one -. If you do have one -, you can pass that along.

      If your daughters get a negative from one parent and a positive from the other, they will be positive. They would need to get a negative from each parent to be Rh-.

      Does that make sense?
      @MsGReene

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      • Stephanie

        Hello, I just found out that one of my daughters is RH+ and I’m O+. Can her father be any blood type?

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        • 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 a positive allele, and your child could be Rh+ even if her father was Rh-.

          Do you know your blood type?

          @MsGreene

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  4. 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.

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    • 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

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  5. Manoj rana

    I have a O+ blood type. My parents are B+ (mother) and B- (Father). Is this outcome possible?

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    • 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

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  6. Manoj

    I have a B- blood type. My parents are O+ (mother) and B+ (Father). Is this outcome possible?

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    • Manoj,

      Yes, it is possible for a child to have B- blood if one parent is O+ and the other is B+.

      Best,
      @MsGreene

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  7. Helen

    Hi Dr Greene,My sister is o+ and the husband is b+ ,then there son is o- ..is it possible. Thsnks

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    • 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

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  8. 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

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    • 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

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  9. Lynne

    Hi there,

    My mother is A+ and my father AB+, and I am A-

    Is this possible? 😊

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    • 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

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  10. 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

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    • 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

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  11. 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

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    • 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

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  12. 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.

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    • 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

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  13. 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- ??

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    • Hi Winter,

      Each parent passes down one allele for blood type and one for Rh. In the example you give:
      – The parent with type O blood passed down an O.
      – The parent with type B blood passed down an B.
      – Each parent passed down a negative allele.
      – The child would be type BO, Rh- or B-.

      Here is how that works —

      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 (- -).

      Hope that helps,
      @MsGreene

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  14. Lacey

    How do I figure out if me and my parents have the same blood type

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    • Lacey,

      All three people need to have their blood tested.

      Best,
      @MsGreene

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  15. Chase

    My dad is o+ and my mom is a+ and I am a- is that possible

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    • 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

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  16. 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

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    • Ammu,

      Blood types are comprised of two alleles. The most common are A, B and O.

      If someone is blood type O, both alleles are O (OO) and he or she can only pass down an O.

      If someone is blood type B, he or she can have two Bs (BB) or one B and one O (BO). He or she can pass down either a B or an O.

      Likewise, each person has two Rh alleles – Positive (+) or Negative (-).

      If someone is Rh-, both alleles are negative (- -).

      If someone is Rh+, both alleles can be positive (++) or one can be positive and one can be negative (+-).

      In the example you give. the mum can only pass down O and -. The father can pass down B or O and positive (+) or negative (-). Each of their children can be B+, B-, O+ or O-.

      Hope that helps,
      @MsGreene

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  17. 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.

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    • 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

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      • Angie

        Thank you that was my understanding also.

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  18. steph

    Can an a+ mother and an a- father conceive an o rhesus negative blood group child

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    • 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

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      • 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

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        • 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

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  19. 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

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    • 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

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      • 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

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  20. gittik

    Hi my blood group is a- and my mother blood group is a+ and my father is b+ its possible.

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    • Gittik,

      Yes, this is a possible combination.

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

      Best,
      @MsGreene

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      • 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!

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        • 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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  21. 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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  22. 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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  23. 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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  24. 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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  25. 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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  26. 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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  27. 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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  28. 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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  29. 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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  30. 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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  31. 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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  32. 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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  33. 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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  34. 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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  35. 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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  36. 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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  37. 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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      • Shawn

        Dr green,
        I have 0- type both my parents have A+ and my older brother has A+. Is that possible?

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        • Hi Shawn,

          Yes it is possible for two A+ parents to have a child who is O-.

          Blood types are comprised of two alleles. Each parent pass down one.

          Type A blood is either AA or AO.

          If both parents are AO, they can each pass down the O allele and their child would be type O.

          Similarly, the Rh system is made of positive (+) and negative (-) alleles.

          People who are + can be ++ or +-.

          If two parents are +-, each one could pass down the – allele and their child would be – – or Rh-.

          I hope that’s helpful.

          Best,
          @MsGreene

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  38. 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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  39. 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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  40. 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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  41. 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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    • Hi T’Anna,

      Blood types are comprised of two alleles. These are A, B and O. A and B are dominant and O is recessive. If a person is type B, he or she can be BB or BO because the O is recessive. If a person is type O he or she is OO.

      Similarly, Rh+ is dominant and Rh- is recessive. If a person is Rh+ he or she can be +- or ++. If a person is Rh- they are –.

      Here’s how that could look:

      – If one parent is B (BB or BO) and the other is O (OO) their children can be type B (in this case BO) or type O (OO).

      – If both parents are Rh+ each one can pass down a – or a + allele, so their children can be either Rh+ or Rh-.

      I hope that is helpful.

      Best,
      @MsGreene

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  42. 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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  43. 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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  44. 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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    • Dear MK,

      I can see how this difference in stories would be upsetting — especially since your mother is no longer with you.

      Here is what I can say, blood types are comprised of two alleles. The most common ones are A, B (both dominant) and O (recessive). Each person get one from their mother and one from their father.

      A person with type A blood can have two A alleles or one A and one O – AA or AO. A person with type O has two O alleles – OO.

      The Rh system is independent of the ABO system. In this system, the postives are dominant and the negatives are recessive. A person who is Rh- at two negative alleles or – -.

      If a person is A-, he or she had to have gotten an A allele from one parent, but the other could have provided an O. To be Rh-, he or she had to get negatives from both parents, but that is completely possible even if both parents are Rh+, if they both were + – (of if either of them were Rh-, they would automatically pass down a negative Rh allele).

      I don’t know where you might go to find out your mother’s blood type. It might be associated with her medical records. If she had a recent surgery, it should be in the hospital’s records, but records are private and you may not be able to get access to them.

      Since your father is still living, you could do a DNA test for you and your father and determine if he is your father.

      I’m sorry I can’t be more helpful.

      @MsGreene
      Co-fouonder and Executive Producer, DrGreene.com

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  45. 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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    • Hi Kara,

      Both parents contribute to their child’s blood type. Each contribute one Rh allele. This is inherited independently of the ABO blood type alleles. There are 2 different alleles for the Rh factor: Rh+ and Rh-. A person who is “Rh positive” or “Rh+” could have two Rh+ alleles, but since the Rh- allele is recessive, a person is Rh+ even if only one allele is positive and the other is negative.

      The bottom line is, even if both parents are Rh+, their child can be Rh-. If both parents are Rh-, their children can only be Rh- since both parent can only provide an Rh- allele.

      I hope that’s helpful.
      @MsGreene

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  46. 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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  47. 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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  48. 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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    • Hi Jeeva,

      Blood types are comprised of two alleles, one from each parent. A and B are dominant and O is recessive. Rh factor is either + or -. Rh+ is dominant and Rh- is recessive.

      Blood type B can be BB or BO. Blood type O is always OO. If one parent is BO and the other is OO, then then they could have an O child.

      Rh- is always –. If both parents are +-, their blood types would be Rh+, but they could both pass the – on to their child and the child would be Rh-.

      In this way, it’s possible for a B+ parent and an O+ parent to have an O- child.

      Hope that makes sense.
      @MsGreene

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  49. DeBorah

    Is it possible for two A++ parents have an 0–baby?

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    • DeBorah,

      Blood types are comprised of two alleles, one from each parent. A and B are dominant and O is recessive. Rh factor is either + or -. Rh+ is dominant and Rh- is recessive.

      Blood type A can be AA or AO. If two parents are AO, then then they could have an O child.

      Rh+ could be ++ or +-. If two parents are +- then they can have an Rh- child.

      In this way, it’s possible for two A+ parents to have an O- child.

      Hope that makes sense.
      @MsGreene

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  50. jai

    Is it possible for a child to have a b- blood group with parents having o+ & A+ group?

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  51. 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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  52. 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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  53. 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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    • Hi Joseline,

      Blood types are made up of two alleles. Alleles can be A, B or O. A and B are dominate while O is recessive. Each person gets one from their mother and one from their father.

      Here is what that looks like:
      — Type A Parent = AO or AA
      — Type O Parent = OO
      — Type A Child = A from one parent and O from the other

      In the Rh system, + is dominate and – is recessive. Here is what that look like:
      — Rh- Parent = —
      — Rh+ Parent = +- or —
      — Rh- Child = — (getting negative from each parent)

      If one parent is A and the other is O there is a 75% chance the child will be type A. If one parent is Rh- and the other is Rh+ there is only a 6.25% chance the child will be Rh-, but this combination is totally possible.

      Hope that explains it for you.

      Best,
      @MsGreene

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  54. 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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  55. 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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  56. 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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  57. 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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  58. 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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  59. Samantha

    Can 2 A positive parents make a O negative child? Can someone please help me understand.

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    • Each person as two alleles that make up their blood type.

      A and B are dominate. O is recessive.

      Type A blood can be AA or AO.

      Type O blood is OO.

      If two parents with type A blood are AO, each parent could give a child an O allele, who would then be OO or type O.

      Similarly, + blood is dominate and – blood is recessive. Someone with + blood can be ++ or +/-.

      If both parents with + blood are +/-, each of them can pass a – to their child who would then be — or Rh-.

      Does that all make sense?

      Best,
      @MsGreene

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  60. 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.

      A and B or dominant and O is recessive. 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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  61. 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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  62. Jalaj Gupta

    My parents have B+ blood group. And my blood group is A-.
    Is it possible that am adopted?

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  63. 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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  64. 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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  65. 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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  66. 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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  67. Carla

    Thanks for clearing up this long overdue answer to my question.

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  68. 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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  69. 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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  70. 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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  71. 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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  72. 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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  73. 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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  74. 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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  75. Danielle

    If I am O- does that mean both of my parents are positive?

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  76. 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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  77. 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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  78. 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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  79. 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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  80. 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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  81. 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. A and B are dominant and O is recessive.

      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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  82. 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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  83. 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. As and Bs are dominant and Os are recessive. 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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  84. 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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  85. 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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  86. 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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  87. 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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  88. 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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  89. 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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    • Blood types consist of two alleles. They are either A,B, or O (there are a few other types, but these are the common ones). A and B are dominant. O is recessive:
      – If mom is blood type B, that means she is BB or BO and will pass down either a B or an O allele.
      – If dad is blood type A, he is either AA or AO and will pass down either an A or O allele.

      In this case, the children could be:
      – OO which is type O
      – BO which is type B
      – AO which is type A
      – AB which is type AB

      In other words, it all fits.

      Hope that helps.
      @MsGreene

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  90. D.latha

    Hi,
    If both parents are o+ group, in five member children,3member children’s have o+,last two member children’s are A + ,is it possible….. My mother would n’t take treatment for pregnancy, all are normal deliveries at home…..so why this other blood group….pls give me advice…

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  91. Mimi La fleur

    Mom O + and Dad B + and brothers, O + _O + _O order, but I am A + Is this possible, I note the second son

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    • Blood types consist of two alleles. They are either A,B, or O (there are a few other types, but these are the common ones). A and B are dominant. O is recessive:
      – If mom is blood type O, that means she is OO and will pass down an O allele.
      – If dad is blood type B, he is either BB or BO and will pass down either B or O allele.

      In this case, the children could be:
      – OO which is type O
      – BO which is type B

      Before jumping to any conclusions, talk with your mom and consider retesting. It’s not unusual for someone to remember his or her blood type incorrectly or for there to have been an error somewhere during the testing and reporting process.

      Hope that helps.
      @MsGreene

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      • mimi la fleur

        I’m sure factions and dad and my mom We have re-test cliques doll but in the hospital told me that this is possible through a recessive trait

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        • Perhaps they know more in the hospital than I do. I’m happy to learn. If you have more information, please share.

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          • mimi la fleur

            I am not convinced by answering the hospital so I decided to resort to you and thank you for the answer, so I hope you answer yes or no, please

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  92. Nina

    Both of my parents have blood type O, while I as their daughter is blood type AB, Is it possible?

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  93. Lane Baxter

    My blood type is O positive, My husband is AB(he says it was on his dog tags in the military),one of our children is O positive. No hanky panky, no adoption. Is this possible or is he remembering wrong.

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    • He is likely remembering incorrectly or his blood test was recorded on his dog tags incorrectly, or the test was in error. This is easy enough to sort out with a round of blood tests for all three of you.

      Hope that helps,
      @MsGreene

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  94. John

    Both of my parents are type AB-, my brother and sister are both type AB-, I am type O+. I have discussed my issues with my mother and she refuses to even admit that either I was adopted or that there is even a possibility that I may have been switched at birth. Through research, I learned that another boy was born at the same hospital as I was and both parents are type O+. What do you suggest that I do?

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  95. Rachael

    My blood is O neg and one childish AB positive and one is AB neg so what’s the fathers blood type?

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  96. Leah Bridle

    What would the fathers blood group be??
    I have O positive blood group.
    Child 1 has O negative (male)
    Child 2 has A negative (male)
    Child 3 has O negative (female- twin 1)
    Child 4 has A negative (female -twin 2)

    I find it weird that child 1 has the same blood group as child 3, and child 2 has the same blood group as child 4. Both opposite sexes and child 3 & 4 are twins. What are the odds??

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    • Anonymous

      Father’s blood group could reflect as A(+/-) on the test results. And even though you have O positive, you likely have a hidden negative rhesus. To get a rhesus negative child, you will need (may be recessive) negative rhesus from both parents.

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  97. Christi

    My father is O+ my mother is O and I’m A + with my brother and sister but I have a sister from a other mother that is B+

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    • Christi

      My father is O+ my mother is O and I’m A + with my brother and sister could O make B+ babies

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    • Detra

      My father is O my mother is O I’m A could my father make B+ with some one else

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      • If one parent has type O blood and the other parent has type B blood, there is an 18.75% chance that each of their children will have type B blood.

        Hope that helps,
        @MsGreene
        Co-founder and Executive Producer, DrGreene.com

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  98. Omotola

    I am AS O+and my husband is AA O+ and we have a daughter that is AA O+ could u pls explain all possibilities becos my hubby is asking questions and I am certain she’s ours

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    • I am unclear on the question since you state that her blood type is the same as your husband’s. Can you explain his issues?

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  99. Hope

    My wife blood type is o plus and my blood is A plus and my new born baby Rh posative got juindce .please can you send how the treatment is good?.thank you.

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  100. Stacey

    my parents are both A positive and I am O positive is this possible

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    • Gary

      I’m the same, also as with both my parents, my brother is a pos, did you find out anything?? I think once the doubts in your head it’s hard to shake. Please let me know if you found out anything. Thanks

      Gary

      Scotland

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      • Lyn

        AO+ and AO+/- (commonly called A) can make an O+ Allele baby, because each parent has an O+ allele to pass down.

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    • lin ross

      My mothers bloodgroup was o negative,my father was o positive,all six of us children had opositive blood. .none of us had illness as children please explain.

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    • Susan

      Stacey, it is possible. You inherited your mother’s dna and your father’s. Simply put, you inherited the dominant or recessive blood type gene from each parent. Now given what we know are your parents dominant blood types, A, and your dominant blood type, O, we can deduce that your mother was A dominant and O recessive as well as your dads. So you then inherited the recessive O genes from mom and dad as your dominant blood type gene. My doctor explained this to my husband and I who are both B- and our second child, a daughter, was O- much to our surprise. Lol. This information is good to know! I had no doubt my husband fathered our daughter but I understood his questioning her blood type. I hope this helps and that I have explained it correctly.

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    • Cena

      Yes A positive plus A positive can equal an A or an o baby so don’t worry.

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  101. Paula Bennett

    I have A- blood and was told that when I was born in 1969 I had to have a blood transfusion to change it out because it was fighting against me. Can your blood type be changed like this? Both parents r positive

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  102. Rachel

    How can two parents being both be OO blood type and have a child with A positive?

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    • SUXAA

      VERY MUCH POSSIBLE . BECAUSE MY CHILD HAD 0+ DESPITE ME BEING A+ AND MY HUSBAND BEING A+ . AND IN SHA ALLAH NO CHEATING WAS DONE HERE :). IN YOUR CASE IT WORKED THE OTHER WAY ROUND

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    • Julia

      So sorry, need to retest to make sure results are accurate. O is recessive two O can only produce O children, to have O type you’re both OO so can only give an O to your children, according to modern science. Two A (comment below) are dominent each contributing the recessive allele O resulting in O child. As in AO and AO=OO

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  103. Swapnil

    Hi, we just had a our son. I’m B+ and my wife is B- but our son happens to be A+. Is this possible or hospital should we get his blood group rechecked?

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  104. Ali

    Hi, basically my dad has AB blood type and my mother has either 0 or A + but I’m a A- is that possible??

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    • There are several variables in your scenario making it very difficult to determine if this is a possible combination or not. But this information may be helpful:

      If one parent is AB+ and the child is A- the other parent could be A+, B+, AB+ or O+.
      If one parent is AB- and the child is A- the other parent could be A-, B-, AB- or O-.

      Best,
      @MsGreene

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    • 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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      • hassan

        Me & my wife is o+ but our son is a+ does it means my wife cheated on me please tell me posobilty

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        • Hassan,

          If the types do not seem possible, consider that there could be an error in one of the three blood type tests. It is not unheard of for one of the three tests to be incorrect, reported incorrectly, or remembered differently than reported.

          The best way to determine paternity is by DNA paternity testing.

          Best,
          @MsGreene

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          • hassan

            Please inform me whether it is possible that two o can produce A or B blood type baby? Where modern science says not possible. Please

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          • Dear Hassan,

            As you say, modern science says it is not possible for two parents with type O blood to have a child who is either type A or type B. It is possible for one of the three people to have incorrect test results (testing error), have the results recorded or reported incorrectly, or have one of the people remember the results differently than he or she was told.

            As Dr. Greene says, “These are general rules, though, and exceptions apply. Very rarely, gene mutations may change the rules such that “impossible children” become possible.”

            If you are concerned about your child, is it relatively easy to have DNA paternity testing done. This checks both the father and child’s DNA to look for specific markers and is much more detailed than blood type testing.

            I hope this is helpful.

            Best,
            @MsGreene

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  105. Kathryn c

    My mother is rh negative, my father is O positive. I am type O positive. She had no pregnancy issues with 3 of her children however, her 4th child required transfusions and ended up with severe cerebral palsey. How did the 3 not cause any pregnancy problems?

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  106. laila

    My father is O and my mom is A or B and i am AB is that possible?

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    • Mom

      Yes Laila….it is. My child is AB. Her father is O and I am B. Her maternal grandfather is AB and her paternal great-grandfather is A. There is NO DOUBT of her paternity. Recessive genes do factor in and A and B are dominate. The chart is wrong in our case too.

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      • Jenna

        I think you might be mistaken. I had a the same situation and DNA test proved that the man was not my father. The DR stated that is not possible. In the comment above look at the chart it is not possible

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      • Julia

        Wow, anger at others does not change science. In 30 years of medicine I have never seen a verified case you describe (mom). All issues were resolved one of two ways, either a bad test result or different paternity/maternity.

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    • Jenna

      No it’s not possible

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  107. Roch

    I am B+ and my mother is O-, so what blood type does my father have to be?

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    • Steven

      Hi My son has a blood group of O+, My blood group is B+ & my wife has A+. with our Blood group is it possible to have our kids with O+ blood group? I would really apprecite your feedback. Thanks.

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  108. Missy

    I just found out my dad is o negative and that my mom is b positive. I am ab positive. If I recall genetics correctly my dad cannot truly be my dad. I know that his and my blood types are correct. Can you please confirm or correct my thinking ? Thank you

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      • Missy

        My dad just had heart surgery and is o negative. I was also retested and am ab positive.

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        • There are rare mutations. There are things we don’t know about science. And above all else, I’m not an expert (I’m not a doctor, but I am interested in this topic). That said, you may want to have an honest talk with your mom.

          @MsGreene
          Co-founder and executive producer, DrGreene.com

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          • Mom

            If you are NOT a Doctor and only interested in this topic, then WHY are you answering as if you are??? My child is AB. Her father is O and I am B. Her maternal grandfather is AB and her paternal great-grandfather is A. There is NO DOUBT of her paternity. Recessive genes do factor in and A and B are dominate. The chart is wrong in our case too.

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  109. Holly

    My mums blood group is O and mines A+ so what would that make my dad ?

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  110. FH

    Hi,I am A-,but both my parents are A+.Is it possible?Thanks

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    • Yes. If both parents are blood type A+, each of their children have a 93.75% chance of being blood group A and a 6.25% chance of being Rh-.

      Hope that helps.
      @MsGreene

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  111. deedea

    sorry it me can some one tell me what this mean im a daughter with a+ my borther a+ my dad a+ my mother rh …how this go

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    • Let me see if I can help figure this out.
      You are A+
      Your brother is A+
      Your father is A+
      Your mother is ?

      Are you asking what your mother’s blood type could be?

      Sorry, but I’m having trouble figuring out what your question is.

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      • deedea

        yes my mother rh my dad not rh his a+ .. i sill haveing trouble to.

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        • Hi Deedea,

          Genetics can be confusing! Because blood tests are common many people have questions about the genetic information found in the ABO blood group and Rh system. Blood types are A, B, AB and O. Rh is listed as – or +. This means people can be A+, A-, B+, B-, AB+, AB-, O+ or O-.

          Please read Blood Types 101 and the RH System for an explanation.

          I hope that helps,
          @MsGreene

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          • deedea

            ok thank you but i sill dont know why my mother say to me we dont have the some boold type

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          • I’m not sure what she is basing that on, since I don’t know her blood type (A, B, AB, or O). I’m also not sure what the issue is or what your concerns are, but children don’t necessarily have the same blood type as their parents. Does that help?

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  112. Joann

    Both of my parents had type O blood, I am A+. Is this possible?

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  113. iskandar

    Both my parents have type blood O. Why is it I am a type B? Is this possible?

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  114. Patrick

    My father was O positive and my mother is O negative. I am A negative. How is that possible?

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    • Kitty

      It is not…. Sorry, Patrick.

      Someone had to have an A to contribute. Unless you are one of those extraordinary mutations/exceptions. If you are not, I would make certain to retest your blood type, or have a serious heart to heart with your mother.

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      • Mom

        The more answers I read from you the more angry I am getting!!! Yes it is possible! You yourself are saying “unless you one of those extraordinary mutations”….maybe they are! People keep telling you their parents are O and they are something else. You think everyone of these mothers cheated on their husbands??? Shame on you for answering when you have NO WAY of knowing for sure! Recessive genes have to factor in when A and B are dominate over O. Stop destroying lives!!!!!

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        • T

          Thankyou for saying that. I totally agree.

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        • Anonymous

          I’m O+ and hubby is A+ but our child is B+. Hospital says it can happen but hubby thinks I was cheating. Which I did not!

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        • tiddly

          I read one of your explanation

          “My child is AB. Her father is O and I am B. Her maternal grandfather is AB and her paternal great-grandfather is A. There is NO DOUBT of her paternity. ”

          Your husband cannot, in anyway, be O because an AB child cannot come from an O that is not how genetics work. He might actually be an AO or AB and might have mistaken his blood type because O is a very common blood type despite it being a recessive gene. This is not a simple chart saying this, but scientific proof that have been examined thoroughly from plants to animals, including thousands of people. The chance of this happening would usually come from blood transfusions or organ transplants which will change back to the original blood over time, unless it is bone marrow.

          I think a lot of people’s parents don’t know their blood types and just chose the most common one.

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          • RE: “I think a lot of people’s parents don’t know their blood types and just chose the most common one.” I completely agree. In addition, I believe blood types are sometimes incorrect (whether that is a lab error or a reporting error) or remembered incorrectly.

            If paternity is the issue, doing DNA paternity testing is in order, not relying on blood typing.

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          • Julia

            Amen! Anger over science facts do not change the facts. All answers advocate retesting and having an open communication with parents. There are hundreds of thousands to millions of adoptions, grandparents raising grandchildren as their own, illigitamate births And yes, births resulting from adultery. If truth makes you so angry then this is not the forum for you. This is America and we all have a voice.

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  115. naresh nayak

    My wife and I both have o positive
    blood type. Is it possible let for our
    chilease to be b positive?

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  116. Nikki

    My mom is positive O while my father is O, why do I have an A blood type?

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  117. Jdbek

    My wife and I both have A positive blood type. Is it possible let for our chilease to be A negative?

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    • Jdbek

      Possible for our child

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      • Melissa

        Yes. It can skip a generation so I’m willing to bet someone, either one of your parents or her parents have an Rh negative type.

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  118. Duckie

    My parents share the same blood type which is O. My brother and I fall under the same type, except my younger sister who is a B. Is she my parent’s daughter? I did some research but your in depth answer would be much appreciated.

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  119. deedea

    can some one tell me what this mean .my morther rh my dad a+ my borther a+ sister a+

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    • There is not enough information in your question to be able to interpret, but it is possible for both parents to be Rh+ and have children who are either Rh+ or Rh-. Does that help?

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      • deedea

        my mother rh dad a+ what it mean/

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  120. David Rae

    My partner has blood type 0+ and my daughter has rhesus negative…what would the fathers blood group have to be?

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    • Here is some information that may be helpful to you. For more details see: Blood Types 101: An Introduction to ABO Blood Types and the Rh System.

      “… 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. 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 is helpful.
      @MsGreene

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  121. Terri

    My mother has passed but was RH-. My father is O+. My brother is O- and I am O+. Are we full siblings?

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    • It’s impossible to know from the information that you’ve provided whether or not you are full sibling. But, from this information there’s no reason to doubt that you are full siblings either.

      If one parent it Rh+ and one is Rh-, each of their children has a 75% chance of being Rh+ and a 25% chance of being Rh-.

      For a detailed explanation see Dr. Greene’s Q&A: Blood Types 101: An Introduction to ABO Blood Types and the Rh System.

      Best,
      @MsGreene

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  122. Lisa

    Both parents are O+, my two siblings are O+ however, I am A+. Is this possible? I read somewhere that a mutation can happen. Is this true?

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  123. ruebin

    Can a A positive father and an o neg mother make an a neg baby??

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  124. Jonnie

    I have a twin sister her blood type is B my mother is B my father is O, I am AB negative. I know that it’s possible for twins to be fathered by two different men if conceived within 72 hours of each other. My sister swears that her and I have different fathers. Is that possible. (we are fraternal twins)

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    • Anna

      I am no expert but it is plausible that you and your twin sister have different fathers. Parents with B and O cannot conceive a child of AB blood type, unless you are one of those rare mutations. However it is plausible that a B combined with an O blood type would produce a daughter with B blood type. Therefore it is possible that you may have separate fathers, but before jumping to conclusions I would suggest everyone has their blood type retested and you have a conversation with your mother. Hope this helped.

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  125. A

    I give blood and they told me my blood type is A negative.My mom is A positive and my Dad is O positive.All my grandparents are also positive.My dad wants a DNA test but I keep telling him it is possible?How can I explain it to him?

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    • Here is Dr. Greene’s explanation:

      Rh System
      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. 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 helps!

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    • deedea

      hi my mom D dad A x brother A x me A what this mean do you know

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  126. Stacy

    My blood type is A + (My mothers is A+), My husband blood type is B+ (His mother’s blood type is AB+). I have a son who is 0 + and a son that is A-. Is this possible?

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    • omar

      yes, it is possible. you may have the genotype AO and your husband have the genotype BO, so AO . BO You and your husband have passed down your “recessive” gene “O” to your son, then son would receive the genotype “OO” which is blood type O. Your second son took your dominant gene “A” that is blood type “A”, his negative Rh came from both of you, you and your husband could have the genotype “Dd”, then your second son received the recessive gene “d” from mom and dad and turned out to have acquired the Rh genotype “dd” which is Rh (-) ve.
      hope that of help you.

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  127. Jules

    I never really put too much thought into this until I had my daughter…where do I begin. I remember about a decade ago, my older brother mentioned his blood type was AB( at this time I can’t recall if it was + or -). I didn’t even know what my blood type was until a few years after this, when I had my daughter. I am O+ as well as my daughter is. While I was pregnant with my daughter, I ran into health problems and became a patient of a couple specialists beyond my PCP who inquired about family history to try to have some information to go on. Upon asking my father, I wound up getting no answers. I had asked on numerous occasions for any information. The response I received was “Stop by sometime and we’ll sit down and go over anything.” I did. Four times while I was pregnant. That was literally the ONLY sentence I could get out of him. I wound up having to tell the doctors I was adopted and had no clue what my families medical history was and had my daughter three months early. My parents are now divorced and due to personal reasons, I chose to have nothing more to do with them. Growing up, my mother did have a tendency of well, ‘getting around.’ I guess what I wondering is, is there anyway or any tests that could determine if the person listed as the father on my own birth certificate is in fact my biological father or not without his cooperation? Knowing anything would be nice.

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    • Mrarchery

      No.

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  128. Aley

    So if both of my parents have B+ blood is it possible for me to have O+ or is there a scandal here?

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    • Anna

      It is possible as they could both be BO + which is capable of producing BB+, BO+ OR OO+

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  129. Kristie

    My husband and I were told when our daughter was born almost 27 years ago that she had A+ blood the same as my husband and I. She has had two children and has always been told she was A+. During her blood work for her second pregnancy it came back O+. I said it can’t be were have your delivery card that says A+. The hospital ran the test again and again it came back O+. How can this be?

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  130. Diana

    If I am A+ an my father is B+ an my mother is O- is this possible.

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    • The scenario you outlined is not a possible outcome, but before you jump to any conclusions, it would be wise to re-test all three parties. It’s not uncommon for one or more of the tests to be inaccurate or to be reported inaccurately or remembered differently than reported.

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      • Diana

        No I was tested in the army. Thank you

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        • Still wise to have all three parties re-tested before jumping to any conclusions.

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    • omar

      genetics has always something to say!! if three of you are confirmed with “forward and reverse typing” using a sample of your blood as you mentioned in your query! then i would advise you to go for genetic testing, you and your parents. you don’t know!! all scenarios are possible; mutation, chimera…etc. or one of you might be “phenotypically” typed “A,B, or AB”, but “genetically” your blood type is different from what appear to be in your blood test!! genetic test would reveal the “unknown”. even though, your scenario above seems to be not possible, but with genetic test is POSSIBLE! go for it. no worry.
      hope it is of help to you.

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  131. Yaliet hernandez

    My mom blood type is A+ my dad is O+ it’s possible that’s I am AB- ?

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    • While this is not considered a possible outcome, it’s not uncommon for one of the three test results to be remembered incorrectly, or recorded incorrectly or even possible that the test results are not correct. Other explanations include a sperm donor. Before you jump to conclusions, it’s wise to ask non-threatening questions that include requesting re-testing of blood types.

      @MsGreene (not MD)
      Executive Producer, DrGreene.com

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    • omar

      excluding lab “error”!!! that is “possible”!! we are testing in the lab for (proteins)/Antigens that stick to the surface of your red blood cells. we are NOT testing for “genes”!! you or you parents could have blood typed “phenotypically” as “A”, “O”, or “AB”, but “genetically” you could have different blood type!! yes, that is possible. you and your parents advised to go for genetic test to clarify this (unexpected) outcomes.
      hope it helps. thank you.

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    • Patricia

      Hi my parents are deceased and my mom.I believe me was A positive and my dad well not sure if he was my real dad my mom never had blood test he was O- and I’m A positive. Anything you could tell me from that? Or anything else i can look into feel stuck and have always been confused he was Italian and my mom french and italian.thank you

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  132. shivani

    if mother has AB blood group and father has O blood group is it possible baby will have AB blood group?
    if it is possible then how?

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    • Beth

      No it is not possible as the child will get one gene from its mother and one from its father the child would either have AO (A) or BO (B) blood type

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    • omar

      yes it is possible! through “mutation”, this one scenario. the second scenario is, your father could be a Bombay” blood type! the third scenario is, your mother could be of a rare cis-AB type!! in the later scenario” mother is of genotype AB/O father is O/O. MOM passes down the whole gene “AB” as she is “cis” and DAD passes down his “O” gene, the product would be “AB/O” which is cis-AB and that is how you appeared to be as blood type “AB”.
      is it of help to you?

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  133. Tina

    Hi, I wonder if you can help me, my blood group is B positive and my husband is O positive, my child was born as B negative with Anti C. The Anti C has gone from her blood now, but mine is now B positive with anti C. Please can you tell me how my child has negative blood when my husband and I are both positive and what anti C is.
    Thank you

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    • Beth

      As positive is a dominant gene you only need one copy for that trait to show. So whilst you have positive blood you could have either +- or ++ given your child is negative it is most likely that both you and your husband have +- your child receives one gene from each parent so they may have received negative from both of you resulting in their blood being negative.

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  134. Teodora

    Hello,

    And thank you for the article! I was wondering, as I am AB +, my Mom is B +, and my Dad is O +, what is the possibility that my Dad is not my biological father? Thank you in advance!

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    • There are a few options:
      — One of the three of you isn’t the blood type you think you are. This is pretty common.
      — There was a rare genetic mutation.
      — He’s not your father.

      The first step is to discuss this with your parents. They may be able to solve the mystery. Next you could have all three of your blood types retested. Finally, you could have DNA paternity testing done to resolve any questions.

      Hope that helps,
      @MsGreene

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      • BN

        Hello Teodora,

        If the blood groups that you have mentioned are correct – then clearly they aren’t your parents.

        Cheers!

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    • Mom

      Teodora…I say yes! My daughter is AB. I am B. Her father is O. There is NO DOUBT of her paternity. Her maternal grandfather is AB and her paternal grandfather is A. Recessive genes have to play a part in this and A and B are dominate. The charts are wrong in our case too.

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      • Jenna

        You keep repeating the same thing over and over, no one that knows how the blood types work is believing it. Go get tested and show the results. I had two different DNA centres conduct the same test with the same blood types you speak off and both centres stated the same thing there is no possible way. Oh and the results came back that he was not my father.

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        • Gill

          My mother is 0- i am ab+, we have both been genetically tested and blood types reconfirmed by two different labs and they match our nhs blood typing……and guess what she is my mother and she still has o- and i am still ab+

          So seen as you know all about the blood types and their possibilities explain that. Or are you now going to tell me that its still impossible or wrong?

          Please feel free to get in touch and review all my paperwork but until then i think you should get off your soapbox and accept that just because you didnt get this outcone others cant

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          • Gill,

            This is all very tricky. As Dr. Greene says above, “While there are rare exceptions, the following information on blood types applies to most people.”

            Additionally, while we know a lot about genetics, science is constantly uncovering what we don’t know. Perhaps there are subsets of type or undiscovered types that are yet to be discovered that will explain situations that we think are impossible now, but are in fact merely rare.

            Best,
            @MsGreene

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  135. theresa

    Hi I’m O+ but my sister say they are A+. Can that happen?

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    • If one parent has type O blood and the other has type A blood, then their children could be O or A.

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  136. Wendy

    If one grand parent has type O positive blood type, and one has AB negitive, and heir child is AB negitive, can the grandchild have o positive blood type?

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    • I think I understand your question, but to clarify — one of your parents has AB- blood and you have O+ blood. You’re wondering if there’s any way the parent with AB- blood could pass along O+ blood type because one of his or her parents was O+. Is that correct?

      If one parent is AB, no matter what the other parent’s blood type, the child can only be A, B, or AB. That said, there are rare genetic mutations in blood types and rather common mis-reported blood types. This can be because the test is in error, someone in the chain reported it incorrectly, or someone is remembering it differently than it was reported.

      DNA tests are the best way to determine paternity (and maternity), but simple re-testing of both parents and the child is the best place to start.

      I hope that’s helpful.
      @MsGreene

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  137. Abigail

    Hi! My husband and I are both O+ our daughter born on Oct 4 2015 is A+ how can that be possible?

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    • There are very rare genetic blood type mutations that would result in this combination. More likely one of the three of you are not the blood type that you think you are. This can happen because one of the tests is in error, someone in the chain reported the incorrect blood type, or one of you is remembering it incorrectly.

      It’s probably smart to have all three of you retested.

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  138. Ayesha

    Everyone in my family is A+, like my parents, my sister, uncle, aunty, cousins, grandmother, almost everyone with my grandfather only the exception. He is O+. I do not know my blood group, what could it be?

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    • Ayesha

      Both my parents are A+. My mom’s parents are A+ and O+ and her 2 brothers are also A+. My dad is also A+ positive but I do not know my grandparents’ blood type. My dad’s siblings are all A+. What could be my blood type?????

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      • Two parents with A+ blood can have children with A or O, Rh+ or Rh- blood types.

        For a full eplanation see Dr. Greene’s article Blood Types 102.

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        • Ayesha

          I did a blood type test and found that I am A+.

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          • Thanks for letting us know the results. This field is endlessly fascinating.

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  139. Sonia

    I am A positive and hubby is B positive but our child is O negative. Is that possible?

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    • If one parent is A positive and one parent is B positive their children could be A, B, AB, or O and positive or negative. O negative is the least likely outcome, but it is possible. For a complete explanation see Dr. Greene’s article Blood Types 102.

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    • Jackie

      Yes that is very possible an A gene and B gene can have an O child. And both parents being rh+ can have a rh- baby. Hope this helps

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    • veron fregellana

      my mother is type o and my father is type ab.. is it possible that none of them match my bloodtype?

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      • veron fregellana

        my mother’s bloodtype is o and my father’s bloodtype is ab. my bloodtype is b, is it possible that none of them match my bloodtype?

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        • If one parent has O type blood and the other has AB, their children can only be type A or B.

          For a full explanation, see Dr. Greene’s Q&A Blood Types 102.

          Best,
          @MsGreene

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  140. Alex To

    I am O+ and my wife is A+ with a child of O-. could such be possible. I need full clarification. Thanks.

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    • It is possible for one parent to be O+ the other A+ and their child to be O-. I know, it sounds odd, but there is a 25% chance their child will be type O and a 6.35% chance the child will have Rh- blood. For a full explanation see Dr. Greene’s article: Blood Types 102.

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      • unknown

        Is it possible to have have mother A+ and father O+ =O+ kid?

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        • If one parent has A+ and one parent and O+ blood type there is a 25% chance that each child will have type O blood and a 75% chance that each child will have type A blood. For a details explanation see Dr. Greene’s Q&A Blood Type 102.

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  141. Nikki

    My parents are both O- and my brother is O+ and I just donated my blood and asked for my blood type. They tested a sample of it and said it was most likely B+. Uhm, are they not my parents?! What’s going on?!

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    • Nikki

      I was their first child if that makes a difference. People say I look exactly like my mom, so they have to be my parents?!

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    • Two O- parents can only have O- children, with very rare exceptions of gene mutation.

      There are several explanations — perhaps both parents aren’t O-, one or more of the past blood type tests were in error, one or more of the blood type tests were reported incorrectly, one or more of the parties recorded or are remembering their blood type incorrectly.

      Would your parents be open to a discussion? You could say that you’ve done some research and you think their blood types may be in error. Would they mind being retested? If they are wrong, it would be helpful for them to know in case they ever needed a blood transfusion. If they have something to share with you, this would give them an opportunity to do so.

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      • Nikki

        Hey so I got my accurate blood result mailed in. I turned out to be O+ instead of their guess of B+ (phew at least the letter is right). And my parents keep insisting they’re both O- and I tell them one of them HAS to be O+ but yes, I will definitely get both of them retested.

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  142. Laura

    I am AB-, my ex-husband is A+. Our children are O+ and AB+. Is that feasible given the types of my ex and me?

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    • If one parent has AB- blood and the other has A+ blood, their children can have A, B, or AB blood types and + or -. O+ is not a possible outcome unless there is a very rare genetic mutation.

      If you are concerned, consider having blood types retested or a paternity test.

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  143. Mike

    I asked a 2 part question, the 2nd question was answered I hope you can answer the 1st one.
    I’m the father of 3 adult children & my blood type is O-, my wife and 3 children have the same blood type B+. I’ve attempted to get answers on my own at differint web site’s but it’s to difficult to understand. From what I understand that could not be the case.

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    • Yes, that’s possible. The odds for blood types are for each child and are averaged over large sample sizes. Here’s an example – if a mother was B+ and a father was O- each of their children would have a 75% chance of being type B and a 75% chance of being +. That doesn’t mean that if the couple had four children one would be type O-.

      The odds are reset with each child. These odds only average out in a large data set. An example of this is if you toss a coin there is a 50/50 chance that you will get heads. If you get heads the first time, the second time you are not more likely to get tails. But if you toss it 100 times you are likely to have half heads and half tails. Does that make sense?

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  144. Joseph Betchel

    One parent AB POS,the other Bpos. The child Oneg?All blood types cofirmed.Is this possible??

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    • This is not a combination that is considered possible. As Dr. Greene points out in his post Blood Types 102 “These are general rules, though, and exceptions apply. Very rarely, gene mutations may change the rules such that “impossible children” become possible. Today there are over 600 blood types known (as well as other tissue types called HLA types), which can make paternity testing far more accurate — but still not perfect.”

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  145. Mike

    I’m the father of 3 children, 1 boy & 2 girls, all my children have the same blood type as my wife, is that possible?

    Also I enlisted into the United States Army in 1979, when I enlisted I was told that I was 0+, and that’s what they put on my dog tags. Years later before going overseas during Desart Storm I was told I was 0-, why was that.

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    • Likely one of your tests was in error, recorded incorrectly, or you are remembering it differently than was reported. This is not at all uncommon.

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  146. Kay

    I have A- blood. My son has O- blood. His teacher said it is impossible for him to be my child. Is this correct?

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    • That is not correct. If one parent has A- blood and the child has O- blood, the other parent could have either A- or B- or O- blood.

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  147. Kate

    I am pregnant for the first time and just found out I am ab-. My mother is sure she is a +, and my dad who is recently deceased belived he was a b+, but could also be b-. I e read the both parents need to be negative to produced an ab- child. Is this an impossible situation?

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    • It is possible for an A+ parent and a B+ parent to have an AB- child. For a full explanation, read Blood Types 102 by Dr. Greene.

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  148. Confused

    My mom is O+ Dad is AB+. I am A(RhNeg) All 7 of my siblings have positive blood types. I have 4 kids all of which are all Positive. My question is: Is it possible that My parents are both my biological parents? Is saying “I have RH Negative blood the same as saying just Negative blood type?

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    • Rh- does mean the same thing as Negative or -.

      It is possible for an O+ parent and an AB+ parent to have an A- child.

      For more details see Dr. Greene’s Q&As Blood Types 101 and Blood Types 102.

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    • D.latha

      Hi Dr Greene,
      My blood group is o+
      My husband group is b+
      My daughter o+
      My son what is the blood group?

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      • If one parent is O+ and the other is B+, each of their children will have a 75% chance of having type B blood and a 25% chance of having type O blood. Each child will hae a 93.75% chance of being Rh+ and a 6.25% chance of being Rh-.

        Hope that helps,
        @MsGreene
        Executive Producer, DrGreene.com

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  149. Carla

    I recently found out my brother & I were adopted. He is B positive & I am O positive. Can we be biological brother & sister or have 1 common biological parent?

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    • If one parent is B+ and one parent is O+ their children could be either B or O, + or -.

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  150. Tina

    Hello. My mother (deceased) was type 0-. My father is type B+. There are 4 siblings. The first two are my brother and myself who are A+. The other two are twins with 0+. I have read over and over that my brother and I don’t have the correct blood type from the combo of our parents. Could there be another explanation besides us having a different father… something rare that can occur . All four of us look very similar to each other. I have read that there are instances when someone with A can be mistyped as an 0. Thanks!

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    • There are a few possible explanations — one or more of the blood types could have been recorded in error, the test could have been false, or someone’s memory of his or her blood type could be wrong. In addition, as Dr. Greene points out in his Q&A Blood Types 102 “These are general rules, though, and exceptions apply. Very rarely, gene mutations may change the rules such that “impossible children” become possible. …
      Today there are over 600 blood types known (as well as other tissue types called HLA types), which can make paternity testing far more accurate — but still not perfect.”

      I hope that’s helpful.
      Cheryl

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  151. Julie

    I am AB negative. My parents are deceased, but would they both have needed to be AB negative? Thanks for the info!

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    • Since each parent contributes one gene, your parents could have been A & B, AB & A, AB & B. Make sense?

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      • Julie

        Thanks for the reply! Regarding Rh+ and Rh-, isn’t it more likely that they are both Rh-?
        I found out today that my dad was A negative.

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  152. michelle

    My father is A+ my mother is O+
    All my siblings are O+ only I am the one with A+ . Is it possible ? I mean all my siblings are O+ ..so even mine should be O+ right ?!

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    • If one parent has O+ and one parent and A+ blood type there is a 75% chance that each child will have type A blood and a 25% chance that each child will have type O blood. For a details explanation see Dr. Greene’s Q&A Blood Type 102.

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  153. Matthew

    My Mom is B+ and my Dad is O-. My blood is AB+. Is that possible or should I be suspicious of the milkman?

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    • While this is not considered a possible outcome, keep in mind there may other reasons than the milkman. It’s not uncommon for one of the three test results to be remembered incorrectly, or recorded incorrectly or even possible that the test results are not correct. Other explanations include a sperm donor (not of the milkman variety). Before you jump to conclusions, it’s wise to ask non-threatening questions.

      Cheryl Greene (not MD)
      Executive Producer, DrGreene.com

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  154. nikkigab

    I’m confused. Please help. I am b- husband is ab+ we have one son that is O negative and a newborn that is B positive. Per your research the O Negative child is not his how can that be? I think my husband may not know his blood type.

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    • It is not uncommon for people to remember their blood type incorrectly. In addition, a blood type test can be inaccurate or even mixed up in the lab with another sample. It would be smart to have the two of you and the two children retested if you are interested in sorting this one out.

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  155. rishi

    when blood group of male is A and female is B then new generation is ?

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  156. Carrie

    I am trying to figure this out.
    I am O- my youngest sister just found out she is AB-
    My mom has told me that she is an O as i have questioned my bio father. but with reasearch i see it is not possible for an O to have a AB child. I know for a fact my sister is my mothers and fathers do to medical stuff she has gone through. so i am assuming my mom has lied to me about her blood type to get me to drop it?!?!

    Question is I am correct right??

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    • The scenario you’ve outlined is correct, however, there are rare genetic mutations that can result in blood types that we don’t expect. As Dr. Greene points out in Blood Types 102 “These are general rules, though, and exceptions apply. Very rarely, gene mutations may change the rules such that “impossible children” become possible. The geneticists at Stanford wrote a great explanation to this on the website for The Tech Museum of Innovation.

      Today there are over 600 blood types known (as well as other tissue types called HLA types), which can make paternity testing far more accurate — but still not perfect.”

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  157. Tracy Berry

    My mother was o+ and my dad was o- my blood type is A- with RH. My dads mom was AB- with RH. so from what I read from the last comment my dad probably wasn’t my biological father is that right?

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    • An O+ parent and an O- parent can’t have an AB- child, however, there are rare genetic mutations that can result in blood types that we don’t expect.

      As Dr. Greene points out in Blood Types 102 “These are general rules, though, and exceptions apply. Very rarely, gene mutations may change the rules such that “impossible children” become possible. The geneticists at Stanford wrote a great explanation to this on the website for The Tech Museum of Innovation.

      Today there are over 600 blood types known (as well as other tissue types called HLA types), which can make paternity testing far more accurate — but still not perfect.”

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  158. Tia Night Eagle

    Hello,
    My Father is O positive and my Mother A negative… I am A negative and my sister is B negative my brother is B positive,,,,,, so I’m confused,, are we full siblings?
    Thank you for your time,
    Tia Night Eagle

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    • If one parent is O+ and the other parent is A-, their children can be type A or O, + or -.

      For a full explanation see Dr. Greene’s Q&A Blood Type 102.

      As Dr. Greene says in that article, “These are general rules, though, and exceptions apply. Very rarely, gene mutations may change the rules such that “impossible children” become possible.”

      If you are concerned, DNA testing is the best way to clear things up.

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  159. Cate

    I’m one of 8 children born to the same parents. Both parents are O+. I’m the only child out of the 8 with O- blood group. I have 4 children to my ex husband who is O+ and 2 of them are O+, 2 are O-.

    It seems very odd to me that out of 8 I’m the only one but out of 4 we got 50/50!

    I also have some illnesses that are inherited and I’ve passed to one of my granddaughters. Is it possible my father isn’t my father?

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    • Odds are a strange thing. With two O+ parents each child has a 6.35% chance of having O- blood. That means out of 10,000 children born to two O+ parents 625 of them should have O- blood. But each child is either + or -. It’s like rolling dice. You should get a 6 once out of every six rolls, and yet you don’t. You may get three in a row and not get another the next 100 times you roll. If you roll long enough (unless the dice are loaded) it will average out to 1 in 6 rolls.

      Does that make sense?

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  160. Mishal

    my parent’s blood group is o+ve but mine is B+ve is there any chance for this type?

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    • Two O+ parents can only have children who are O+ or O-. However, as Dr. Greene points out in his Q&A Blood Types 102, “These are general rules, though, and exceptions apply. Very rarely, gene mutations may change the rules such that “impossible children” become possible.”

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  161. Candace brooks

    Hello…
    I just had a baby she is B negative and I am O positive I was just wondering what blood type would her father have to have? Really freaking out. Can you inherit blood type from down the line?

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    • In this scenario, the father would be B+ or AB+. For a full explanation go to Dr. Greene’s Q&A, Blood Types 102.

      Hope that helps!

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    • Candace Brooks

      Hi, me again. Is there possible that babies can inherit a blood type from down the line?

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      • I don’t know what you mean “from down the line”. Do you mean from a previous generation? Such as a grandparent?

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        • Candace Brooks

          Yes.

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          • We all are impacted by our ancestors. In blood types, we get one gene from our father and one from our mother. It is possible in that way for a gene to pass “silently” from a grandparent to a parent, to a grandchild — but that is accounted for in the information I’ve already provided.

            Please keep in mind, as Dr. Greene points out in his Q&A Blood Types 102, “These are general rules, though, and exceptions apply. Very rarely, gene mutations may change the rules such that “impossible children” become possible.”

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  162. Lindsay

    I am one of three children born to the same parents and I am the only one with O- blood group, I found my blood group out when I booked in for my first pregnancy and at the time my Doctor raised her eyebrows but did not pursue it, anyhow I have reason to believe that I am not the biological daughter of my Father and my Parents blood types are as follows:

    Mother O+
    Father O+

    Child 1 O+
    Child 2 O+

    Child 3 ( me ) O-

    My Grandfather is the only person in our Family apart from me who has a negative blood group and he is A-

    As I understand it is possible that he passed on a O+- to my Father, but then wouldn’t my Father have A+- blood grouping as I thought that A was always dominant over O? I am confused by the possible permutations to this issue as it could potentially cause a huge split in our Family with my Father questioning his own paternity as well as trying to resolve my Paternity,

    I have ordered a DNA testing kit which my Father and I will both take so we can finally put this issue to rest but any advice reference my Grandfather not being my Fathers biological child would be very appreciated.

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    • There is a 6.25% chance that every child of two O+ parents will be O-.

      As to your question about your Grandfather’s blood type and what he might have passed to your father — do you know your Grandmother’s blood type? Without that information it’s just speculation.

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  163. Anonymous

    DR. Greene her question was can two O+ parents give birth to an O- Baby? You threw a lot of info out there except for the answer. If your parents are both phenotype O+ O+ then their is no way that they could have an O- Baby..But if they are O+ O- hybrids than yes they could just like an AO or BO can have an OO if they marry one because they two are hybrids If an O- O- marries an O+ O+ yes the baby will be O+ O- but if that son or daughter marries an O+ O+ it could be O+ O- but most likely it would be O+ O+. Likewise if an AA+ person marries a OO+ person the children will be AO+ and if an AO+ person marries an OO+ person the child could be OO+ or AO+. That’s how genes work if the AO+ dads O+ sperm happens to attach itself to the moms O+ egg than the baby will be OO+ or if the A+ sperm attaches itself to the O+ egg the baby will be AO+. If the parents are both AO they could have O or O babies and it works the same way with BB OO BO babies as well. AB is extremely rare blood 3.4% of the worlds population have it and 0.6% have AB- all totaling 4% of the worlds population. O is the most and A is a very close second and B blood is kind of rare as well. I hope this helps. I want to note that AO BO and O+ O- A+ A- B+ B- are hybrids where one acts as a silent business partner but yet can be inherited and fully activated. There is no excuse for we have been aware of this for a long time.

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  164. Michelle young

    I am A neg…is my blood rare? Should I donate my blood regularly?

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    • According to the American Red Cross:

      O+ is the most common blood type. Not all ethnic groups have the same mix of these blood types. Hispanic people, for example, have a relatively high number of O’s, while Asian people have a relatively high number of B’s. The mix of the different blood types in the U.S. population is:

       
      Caucasians
      African American
      Hispanic
      Asian
      O +
      37%
      47%
      53%
      39%
      O –
      8%
      4%
      4%
      1%
      A +
      33%
      24%
      29%
      27%
      A –
      7%
      2%
      2%
      0.5%
      B +
      9%
      18%
      9%
      25%
      B –
      2%
      1%
      1%
      0.4%
      AB +
      3%
      4%
      2%
      7%
      AB –
      1%
      0.3%
      0.2%
      0.1%

      The people with O- blood are universal donors. Only 9 percent of people in the U.S. have O-negative blood type. O-negative blood type donors are universal donors as their blood can be given to people of all blood types. Type O-negative blood is needed in emergencies before the patient’s blood type is known and with newborns who need blood.

      People with A- blood are not universal donors, but if you are a healthy person, donating blood is a great way to help others.

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      • brittney

        If me and my fiance are a type. He is a+ and I’m a- and our son is ab+ is there a possibility of this. Because my fiance is trying to deny it

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        • If one parent is A+ and one is A-, there children will be A+, A-, O+ or O-.

          Before jumping to any conclusions, it’s wise to have everyone’s blood tested again. It’s not unusual for there to be an error in one of the three tests, or the recording, or reporting of one or more of the results. If you still have questions, a DNA test of father and child can be used to determine paternity.

          Hope that helps,
          @MsGreene

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  165. Michelle

    If I am O rh negative and my husband is B positive. What are the possibilities of blood types of our children?

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    • Hi Michelle,

      There is a 75% chance each of your children will have B blood type and 25% chance of O. There is also a 75% chance each of your children will have Rh+ blood and a 25% chance of Rh-. So the possible combinations are:

        O+
        O-
        B+
        B-

      Hope that helps.

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  166. Alison

    I (mother) have O- blood and my daughter has B- blood. Can her dad be a B+ blood type?

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    • In this scenario, the father could be B- or AB-. If you have questions, it’s always smart to retest before jumping to any conclusions.

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    • Candace Brooks

      Same question here.

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  167. Linda

    When I was pregnant with my son, I found out my blood type, which is A+. I had told my mom. She kind of freaked and said that’s wrong — dad and I have O. I am totally confused. My dad since has passed. His dog tags say he has O, I’m not sure if neg or pos. Can you help me try to figure this out? Thank you.

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    • Two O blood type parents can’t have a child with A blood type. It’s not uncommon for one of the three blood types to be reported incorrectly, however.

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  168. Holly

    My mother is a+ and my father is b+ but I’m o-! There is question if my father is truly my blood father. I was just wondering if that is possible.

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  169. Nadia

    My mother’s whole family (grandparents, parents and siblings) are all A+ and my dad’s whole family are all O- (grandparents, parents and siblings). My sister and brother are both A+ but I am O+. Am I right in saying that it can’t be correct?

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  170. Gabywd

    I just found out in my 3 rd pregnancy that I am B – , my husband is O + and both my parents are B + . My first two daughters are B + and at the time I thought I was B+ and I didn’t have any “shots” is this possible? I have been tested 3 times and they all come back B negative very confused !

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  171. Sarah

    Hello my blood type is O- and my both parents is O+ is that possible???!

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    • It is uncommon, but possible. In fact there isa 6.25% chance that two parents with O+ blood will have a child with O- blood.

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  172. jallusion

    Hi my family all their blood type s are o++ or o+- and I’m the 4 child but I’m the only 1 with b– what’s wrong with that’s?

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    • This is possible. For instance, if one parent had A- and the other had B+, they could have have children with either – or + Rh and could have children that are A, B, AB, or O.

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  173. Elena

    hello,
    I have A+ and my husband has B+, our deceased child was AB-.
    Could this be possible?
    they didn’t find a diagnostic, could be something linked to her blood type?
    thank you so much

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    • I’m so sorry for your loss.

      It is possible for an A+ parent and a B+ parent to have a child with AB- blood. I can not tell you if it had any impact on your child’s health. Perhaps you could visit a geneticist for more information.

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  174. olue

    I am o+ so also my wife but our first daughter was o-. can it be possible? Though we are all AA genotype.

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  175. Hemant

    is it possible that fathers blood g is AB- , mothers blood g B- …than daughters will be A-….

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  176. Beki

    Hi I am O- blood type and my daughter is AB- her fathers blood type is unknown, what could his be?
    Because I’ve read that it’s not possible for an O- female to have an AB- baby?

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  177. Brittany

    I am O+ my daughter is AB- tested at birth due to some complications and I know for a fact that I’m O+ because I received blood… Not the doctor was confused and scratching his head when talking to me about it but… O+ can have AB-

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  178. Regina

    Hi, my mother is A+, my sisters are A+ and A-, I am O. Is there anyway to decipher what my father’s blood type is?

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    • smarty p

      is that a homework assignment?

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      • Jane

        He also could have been A or B or O.

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  179. KB

    O+ mother, A- father. O- negative. Could that be? How is the RH factor determined? I was tested by a blood center because I donate, I was told my childs type by a nurse @ her pediatricians office and the father thinks that’s what his is. Just wanting to double check that a child could be O- if the mother is O+. —-Thank you.

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    • A mother with O+ blood and a father with A- blood have a 75% chance of having a child with type A blood and a 25% chance of having type O blood.

      A mother with O+ blood and a father with A- blood have a 75% chance of having a child with Rh+ blood and a 25% chance of Rh- blood.

      For a full explanation, see Dr. Greene’s article Blood Types 101: An Introduction to ABO Blood Types and the Rh System.

      Hope that helps!

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  180. Carolyn

    I’m an AB- and I just found out my father is O+ can this be possible? I always thought if I was AB- that my parents would have Co-dominant alleles AA, BB, or AB for me to result in AB. SO you can imagine my surprise when I heard that my father is O+ How can this be possible? Unless…

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    • That combination is not possible, but blood tests are sometimes wrong as are memories of test results. It’s wise to double check, before making assumptions.

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  181. Fathimakm

    Sir my mom blood group is A1+ and my father blood group is B+ and my blood group is A1B+. Is this blood group is considered in type of blood group many are telling this blood group is not considered now and weather. Is A1B+ considered?

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  182. abhaille

    We have three children. I’m O+ and we don’t know what my husband is. Two children are O- and one is O+.

    I’m thinking he’s O-. What are the odds?

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  183. Anonymous

    sir…i am having AB positive bloodgroup and my wife B positive bloodgroup and my child O positive ..is this possible

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  184. Alex

    My parents has type O as their blood type. And when I was diagnose with dengue the doctor said that my blood type is AB. Is it possible for me to have that blood type even though my parents are both type O?

    Hoping for your response. Thanks.

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  185. Nikita

    My blood group is O+ and my Husband is B+ now our child blood group is AB+. Is it possible?

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    • Children of an O+ parent and a B+ parent have a 85% chance of being blood group B and a 25% chance of being blood group O. Each child of those two parents have a 93.75% chance of being Rh+.

      Perhaps it’s time to have both parents and the child re-tested. Or consider that one of the parents is not the biological parent.

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  186. Backatchatwice

    I have a question, not a comment.
    What are the odds of A+ and B+ parents having a B- child?
    Would the A+ mother reject the B- child at some point;
    like with an Rh negative mother and a Rh positive fetus?

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  187. mary

    Both my parents are deceased. Is it possible to obtain their blood type results from a source somewhere? Mine is rh positive with little c antibodies since the birth of my first child. I would greatly appreciate some help.

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  188. Jenni

    I recently found out I was blood group A, but my parents both are pretty sure they are both O. If this is correct does this mean they are not my parents?

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  189. Peter Ngu (Wu)

    I do not know my deceased parents blood types. All my brothers and sisters (7 of them) have Type A Blood type. I am the youngest and have Type O blood type. The one above me is my sister who is 8 years older than me. Is this type of non similarities possible. Hope to hear from you soon. Thank you

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    • If one parent has type O blood and the other is type A, 75% of their children would have type A blood and 25% would have type O blood. What that means is each child has a 75% chance of having type A blood and a 25% chance of having type O blood. Theoretically, that means 2 out of 8 children would be type A, but in reality, each child could be either type A or type O.

      For a detailed explanation — Blood Types 102: The Role of A, B, O, and AB Groups In Determining Paternity.

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  190. EMMA

    I am O+ while my mum is O-. What blood type/group will my father be. This question has been killing me as my mum have no idea and I discovered my dad is type A, could he be my dad? Really urgent.
    Thanks

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      • savannah Ray

        My mother and father are both O- and I’m O+. Is that possible?

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        • If both parents are O-, their children will be O-. But often one of the three parties either don’t remember their test results correctly, or the tests were wrong. Testing errors do happen. Before jumping to conclusions, you should all re-test. If this is a serious concern, paternity testing is the most accurate way to determine who your father is.

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  191. Annemarie

    if I am O positive and my mother is O positive and my father is AB negative RH does this mean he is a match or not please get back to me asap would appreicaite it thanks x

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  192. Chanel

    my sister and I have grown up being told we have different dads. We have the same mum. Yet I never met my father. We recently gave blood and found out we are both B- blood. Does this mean we do have the same father? Our parents have passed so we can’t ask them.

    Many many thanks

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  193. Cleasy

    My wife has O neg blood type and I am AB pos but our son is B neg. I thought AB would have been the dominant type.

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  194. nessie

    Hi there, both my parents are A+ve and I am A-ve ? According to my family, no one is negative? Can that be? My sister is A+ve.

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  195. Evelyn Bakic

    I am O+ i have 3 daughters my eldest is O+, second is A+, and the baby is not typed yet. What would be my husbands blood type? He is not a fan of needles so getting him tested just for typing is out of the question.

    Thanks

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    • anonymous

      Since you are O type and have an O type child and an A type child, this means the other half has to be A type. As per + or – could be either. Your third child can be either an A or O + or -.

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  196. Clare

    I’m O Rh Negative and we found out my daughter is O positive due to her needing tests when she was very small.

    We also have a little boy who we don’t know his blood group and my husband doesn’t know his – any ideas as to if my son would also be an O positive and would my husband also be O?

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  197. karysma

    My moms B- and I’m Ab+ and my dad doesn’t really know his blood type. She said he was either B or O. But then I told him I couldn’t be his daughter if he was so I asked him again. Now he is saying he is A+. What should I do?

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    • You could have your answer with a simple blood test from your dad. You could say something like, “Dad, I’d like to know the blood types of both you and mom. This could come in handy for health purposes down the road and it would put my mind at ease about our relationship. Is that something you can do for me?”

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  198. sabina

    I’m O positive and my husband is O negative. Are there chances my child will have rh negative?

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  199. kerry till

    I’m a rhesus b negative and my sister is ab positive,is it possible we could be full sisters?

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  200. Febi Francis

    both my parents are o+ and I’m AB- is this possible

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  201. Diana

    I have a+ blood an my mother is o+ an my father is b+.. I don’t think they are my parent what do I do?

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    • You are correct that those combinations can not occur. The first step is to discuss your fears with your parents. They may say they are indeed your biological parents, and one of the blood types is incorrect. It’s pretty easy to have all three of you re-tested. Or this may open the door to a conversation about your adoption.

      If you think there is a possibility that your mother is your biological mother, but your father isn’t your biological father, you may want to talk with her alone before including your father in the conversation.

      Unless you have reason to think your parents are hiding something from you, this should be a calm conversation that simply explains your heritage more fully.

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  202. Sharon

    Please help. Desperate!
    My Parents both have RH- blood types.
    I am RH+
    How?
    I was born with severe Anemia. .mother needed Rogram shots after me.
    My Uncle is RH+ !!!!
    Please tell me if my parents couldve produced me..or did the someone mess up!!
    Im 54 I dont mind anymore.

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  203. dt

    I was watching a TV programme where the dad was ab and mum o and the baby was o, so it was concluded that the dad was not at all the dad!

    My eldest sister is type o and our mum is o but dad ab rh negative. I am A rh negative as is my other sister. Could our dad be my eldest sisters dad? She is o positive like mum, but we are all A negative and dad is AB negative! She’s the first born, is she my dad’s? From the info on here she can’t be?

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  204. Yvonne Shepherd

    I have been diagnosed with chronic kidney disease. It does not run in my dad’s side of the family and I have never met my birth mother So I’m assuming I inherited it from her side. I’m trying to figure out what blood type my birth Mom would be. My Dad is O+ and I am A- rh- factor . Could anyone please help?

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  205. Jan

    Hi my parents are both O+ I am A- is this possible

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    • Tina

      No I would be asking your parents some questions sorry but it not possible for to 2 Os to have an A

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  206. Mark Trevellick

    Can a b poss father and a o poss mother have a o neg baby

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    • Tina

      Yes

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  207. Freida

    I have a question, my Dad is O+, but my Mom is A+! My question is, is she my mother?

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    • Freida

      Sorry just read my question, I am O+ my mother is A+ can she be my mother? My dad was O+!

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      • Andy

        Yes, if your parents are A and 0, the child can either be 0 or A.

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  208. figo

    I was tested B+ blood group and my wife to be is 0+ blood group. And in my country, Nigeria, there is this genotype blood that is not familiar to other doctors outside the country and that is AA, AS, SS blood genotype. Universally where does this blood genotypes falls into? Please I will be happy to see my questions answered.

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  209. Carla

    If both parents have A positive blood, can they have a O negative child ?

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    • The short answer is yes.

      If two parents both have AO +- genes, they will both have A positive blood and about 1/4 of their kids would be type O and about 1/4 of their kids would be Rh negative, so about one out of sixteen times they would have an O negative child.

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  210. shefali

    hi…..i belong to india,rajasthan

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  211. Rohit

    Well b+ is a blood group for a CHILD. Now A+ is mother and O+ is father.
    What is the chance of getting a B+ CHILD??

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    • Evan

      I don’t think it is possible. According to my Introductory Bioscience lecturer the only way a child can be a member of the B blood group is if one of the parents provides the B to the genotype. In simple terms a member of the A blood group can only be AA or AO while a member of the O blood group can only have oo. As neither parent has the B antigen markers in their blood no offspring of this relationship can be blood group B.

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      • Sandra

        Dr. Greene,
        Is this reply to the A+ & O+ parents w/ a B+ child correct?

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  212. Afna

    i’m Afna…My question…..Parents having AB+(Father,Mother)….but children having(1st:AB+,2nd:A+,3ard:AB+).please explain its chances….?

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  213. shefali

    my sister has blood grp ab+ and both of my parents hav o + is this possible. She is first child of my parents

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    • Tanvir

      Shefali, can i know where you are from? I am trying to research on this matter…I wont give the verdict, but the cross typing doesn’t really show the possibility of making AB+ out of two O+ parents…But again its all GENETICS…and needs more research! Are you from Bangladesh/India or any of SEA?

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  214. Catherine

    My parents are both O+ but in a recent test my blood seemed to be B+ is that possible?

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    • Tanvir

      Are you first child?

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      • Rohit

        Dear Tanvir,
        Yes I am the first child of my parents .
        Or no???
        Tell me my Blood Group is B+ and Fathers group is O+ my mother is A+.
        Now are they my real parents?? or Tapake Khazuur pe ?

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    • maddy

      both of my parents are b + n I m o+ but younger sis is b+.., in science, everything is possible so chill

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  215. pamy

    I am from India, I m a man of O negative blood. Can I marry to O positive women? What will happen to my baby? Can I marry to A blood group? What will happen to my baby? Can I marry to B blood group women? What will happen to my baby? And my last questions is I heard that all the guys who have A negative blood have less genes which lead to no children in life? Is that true?

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    • abhaille

      You should have no problem marrying any woman that would have you. O negative is the universal donor. Women are the ones that have the trouble having negative blood type when having children.

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  216. Carol

    Can a person have blood group O and neither parent have that blood group?

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  217. I. McNutt

    I was born to a mother with AB- and a father as O+. I was the second child and mom never had any shots after her first birth or when carrying me. Can this cause health issues for the second child? And if so what can the issues be? I have had a lot of health issues my entire life one thing after another could this be why?

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      • Diana Harris

        I can truly relate to I. McNutt in that I’m also the 2nd baby of Rh incompatible parents (my mother being untreated since it was the 1950’s). However, in my case my elder sister was actually the blue baby, born in ’54 she died after just a couple of days.

        I always thought of myself as a miracle baby since I should’ve been the one to suffer that fate being 2nd, yet was born healthy in ’56. When my mother was almost 40 (this essentially was her last chance to have her long desired baby girl).

        I’ve often wondered how I was unscathed, perhaps you can answer this? Anyhow like I. McNutt I’ve suffered a myriad of chronic health ailments even as an adult – between the age of 25-30 is when they presented (psoriasis, psoriatic arthritis, fibromyalgia, chronic fatigue, fibrocystic breasts, hypothyroidism, osteopenia which now is osteoporosis, neuropathy) & have wondered as well if this was connected to the Rh factor situation. I’ve felt like I’m in my 80’s since I was 30 being crippled up in pain, constantly at doctors & labs, medications etc.

        As a child I nearly died from complications of bronchitis when I was 2, had recurrent bouts of hives (even into adulthood) & the usual childhood illnesses (measles, mumps, chicken pox). I’ve been severely nearsighted since I was 7 (Coke bottle glasses) which now has put me at high risk for some type of retinal detachment & bleeding so must be monitored at least every 6 mos. I’m 58, but the last 30 years (when I was still relatively young) have really drained me & I’ve a hard time envisioning another 30 years of pain & struggle.

        I can’t help thinking if my health conditions stem from the Rh issue then something could be done that would target the source & I finally could get better. I recently was diagnosed with major depressive disorder & that has to do with all of this & how life is getting harder for me – just to do the basics. On the Yahoo Q & A another Rh person had written similarly how they’ve suffered with their health & their siblings had all died by their 40’s.

        Have there been any studies done of babies (born prior to 1963) of Rh incompatible parents & their health outcomes as they mature? Are those of us writing in who are sick merely flukes? is the Rh incompatibility & illness just coincidental or is there a pattern & one worth investigating? I welcome & would be most grateful for any information & opinions you could provide.

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  218. John J

    If both parents are O+ , and they have three kids that are O+. Is it possible for a fourth child to be O-?

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  219. stumped

    I have 2 children with o+ blood type, I am o+ and my husband is o+, he has a daughter from another woman and this daughter has ab- blood type, the daughter says her mothers blood type was also ab-. Is is possible that this is his daughter?

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  220. payal

    My brother blood group is “O”positive and my sister in law blood group is “AB” negative but my nephew blood group is “B” positive it is possible or not?? Plz help us..

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    • It’s not the most common blood type from this mother and father, but this is possible.

      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. In other words, both parents must have type O blood for their children to have type O blood.

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  221. Rose

    My parents were blood o group but my brother is a resus negative mine is a possitive can this be ??

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    • From the information you’ve given, it’s impossible to know for sure. If both your parents were O- all their children would be negative, but if either of them were O+, this is a possible combination.

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  222. christy

    Yes my blood type is ab+ and one of my daughters just found out her blood type is b- Her father is adopted and he doesn’t know his blood type. There is a chance he could not be the real father, so what would his blood type have to be to be compatible for him to be the real father? Please help!!!

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    • Your daughter’s father would have blood type A+, B+, AB+, or O+.

      Hope that helps.

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  223. Edward Hines

    My mom is O+ and dad is B+, how can I be A+, help please?

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    • Linda

      Hello Edward,
      Did your question ever get answered?
      I have the same situation and further digging has pulled up some anomalies that could make this true…

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    • omar

      Hi Edward.
      genetics has the answer! although, it looks not possible with Mendel’s rule of inheritance, these rules could be broken!! you or one of your parents could have a mutation somewhere! or one of your parents could have a blood type “genetically” different from what is appear to be in their blood “phenotype”!! in other way, one of your parent might have a “hidden” A gene that is not appeared in their blood phenotype!! this hidden A gene carried on sperm or ovum of your parents and passed to you!! it is worth thinking to go for genetic test this may solve the “unexpected” outcomes.
      hope i clarified it to you. thank u.

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  224. Glen

    My parents and brothers and sisters are all O type not sure about pos/neg. Why am I AB positive? Is there something my parents should tell me?

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    • C

      Maybe there’s something at least one of your parents should be telling you. And your dad. :)

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      • Before jumping to conclusions, you may want to consider a few key questions:

        • Was I wanted?
        • Do my parents love me?
        • Will it hurt my father if I open this can of worms?

        You may have been a much desired child that your parents were able to conceive with the help of a sperm donor.

        Or one of the three tests may be wrong.

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    • omar

      Hello Glen,
      if you consider “mutation”, that is possible!!! you and your parents are advised to do genetic testing for clarification of these (rare) outcomes. if you exclude blood type test error.

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  225. sabillah

    My parents both are o+ and mine is B+. Is that possible? I’ve been wondering.

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    • Two O+ parents can’t have a B+ child, but consider:
      — Perhaps all the tests aren’t correct. Test errors do happen.
      — Perhaps someone’s memory of his or her test results are wrong.
      — Even “impossible” results happen. They are very rare, but genetic mutation is real.

      If this is of concern, consider DNA testing to determine paternity.

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  226. nav

    sir…i am having AB positive bloodgroup and my wife B positive bloodgroup and my child O positive ..is this possible??

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  227. Chris

    I saw a case where both parents are O+ but all their children are A+. How can i reconcile these?

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    • Pat

      Both my mom and dad are gone, both of them are 0 positive, including my brother , but I am A Positive

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  228. marwan john

    am b negative and my wife o negative it is posssible we have a positive child ???

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  229. Shirley

    Father A negative Mother O Negative child A positive. Is it possible this man to be the dad?

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    • Ashleigh

      YES… II just had my son 2 days ago… I am A- and his father is O+… Our son is A+… A type is dominate over O type and when you have a – + combo the + is dominate… So you would end up with an A+ Baby…

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  230. Courtney

    My mother is ab negative and my father is o negative. I’m o negative. How is this possible if an ab blood type can’t parent a o blood type?

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    • Michelle

      I am almost 100% sure that my husband tested AB-. I was pregnant and found out to be negative, so we tested my husband. I am O-, both my children are O- as well. The only reason I say almost 100% sure dad is Ab, is because after reading this article I began to question my memory..lol..I cannot find the labs report to check for sure. But after this article, I’m extremely curious to find out for sure. Just sharing.

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  231. Mainlay Jasn

    Suresh Mathur … My mother is O+. My dad is O+, but I’m O-. My little brother is O+.
    So, you’re wrong.

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    • Alexis Brown

      He is not wrong however, you are mistaken. Each person has 2 RH factors either ++, +- or –. He explained all variables in his examples.

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      • Courtney

        Mainlay was speaking to someone who commented and was wrong. Js.

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  232. Suresh Mathur

    Hi,
    Me and my wife both blood group is O+, and my new born baby boy also O positive.
    I think that if parent are O+, all baby will O+.
    Thanks Doc For nice article.

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  233. Liana Hernandez

    Hi my blood type is A + and my husbands is A- so when our child was born she was an O + . We took a DNA test to confirm which proved this can happen.

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  234. patty balser

    If I have RHO negative blood, what would my parents blood have to be?

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  235. subir dutta

    my blood groupe is A ..and my wife is B …but my son’s groupe is O ..is it possible

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    • Alka Gupta

      Yes.. It it is possible coz u have A group means u r carrying A nd O gene nd ur wife have B group means she is carrying B and O gene…so ur baby can take one O from u nd another O from ur wife nd ur baby’s blood group vil be O

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    • davidpaulabraham

      My wife and i are 0+ what is my baby blood group???

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    • Srinivas

      Mother A positive,Father B positive.child O negative.Is it possible

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  236. mich

    Hallo

    Can a baby’s blood be B+ if the mother is A- and the father is type O (not sure if – or +)?

    Please help.

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    • Harsha

      I just saw your query…..i am not good at biology it cannot be possible to have B+ if parents are A- and o(+ or -)….you just refer to this link http://www.endmemo.com/medical/bloodtype.php ….. the result i got is NO

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    • Alka Gupta

      No it is not possible… One of the two parents must have B gene … Otherwise it is not possible.

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  237. tyshauna joiner

    Can o positive people have a healthy baby?

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    • anita k

      We are both o+. Won’t our baby have difficulties in health?

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  238. Rajesh p

    Docter I am simply verifing my blood group is O positive and wife blood group is B positive but my baby is b positive it is possible sir

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  239. yash

    THANK YOU SIR I HAVE FOUND THE ANSWER FOR MY QUESTION IN THE ARTICLE BLOOD TYPES 102

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  240. yash

    Sir,I have a question my cousin’s parents are B+ and my elder cousin brother has B+ but the case of his younger brother he has O+ IS THIS POSSIBLE ? Please reply to this on my mail address.
    THANK YOU

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  241. chantelle

    As I understand I was a “blue baby” during birth and needed an emergency blood transfusion.

    My Mother is A+
    My Father is A+
    But I am AB+ (this is impossible because two A… cant produce an AB)

    Can this be caused due to the blood transfusion that I receaved after my mother gave birth to me?

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  242. Aaron Forrest

    Hi my mother is o negative. I don’t know what my fathers blood type is, but mine is ab positive. Research I have done on the internet says this is impossible. Can some one please explain?

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    • Courtney

      Your father might have ab blood. it does say an ab can’t parent an o

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  243. Kyle

    Both the wife and I have O+ blood. How can we have a baby with A-? I understand that we both are (+,-) so we can have a child that is O- but how is it that the baby is A? The doctor told us that this is very rare. I just want to understand how.

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    • Becky

      I am very interested in any answers you find on this subject, Kyle.

      I am very obviously not adopted, but just recently I found out that both my parents are type O (dad is O+), two out of three siblings are O+ (one sister doesn’t know her type), and all three of my children are O+. I am type B (I don’t know whether its positive or negative). To my knowledge I’ve never had a blood transfusion. Everything I’ve searched online states that this is not possible.

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      • Fiona

        I’m very interested in what you have found out as well. Both of my parents are O+ and I am B+. I’m just very confused as from my very basic Biology it’s not possible?

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    • Sabrina

      Same has happened to me and my husband. He is o- and I am o+ but our daughter was born A+. I hear about this happening in many other cases.

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  244. Jules

    Hi my mom is an o+ and my father is a b- and I found out during the labs for my pregnancy that I’m an a+. That isn’t possible is it?? I have other reasons to be suspicious but does medically prove that it is impossible for them to both be my biological parents?

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  245. Anushree

    So my mom’s blood group is B-ve while my dad’s is B+ve, but I’m AB+ve. They say that in rare cases it is possible for the blood group not to match, but I’m still skeptical about it. Can you help?

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  246. Katie webb

    My blood type is b-and my twins are o-my ex husband doesnt think he is the father but his blood type is o- as well could that mean he is the dad

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    • Tish

      I’m O- and my son is O-, my husband is O+, there is no question he is from us both as he was born by in vitro fertilization.

      Ha ha — unless he was ‘switched’ at birth, but highly unlikely-he looks like both of us no doubt.

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  247. "M"

    My mom is A+ , my sister is O- and I am B-. Is this possible and so we have the same dad?

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  248. love

    What about pregnancy if my blood group is b- and my wife o+?

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  249. Rajesh p mysore

    Docter sir I’m confused. My blood group is O positive and my wife’s blood group is B positive and my son blood group is B positive. Is it possible?

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    • Henk

      Yes, this is possible.
      The gene types of blood group B are BB and BO. The gene types of blood group O is OO. Your child must have gene type BO (the B inherited from your wife and the O inherited from you) making him having blood group B.

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  250. sai

    If you have parents with same O+ blood, would it be possible if they bear an A+ offspring? Please answer because I really want to know if I am really their daughter.

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  251. Larry Richardson

    Hi Dr. Greene.

    Both of my parents are deceased. When my mother was alive, she told me she had the rarest form of blood: AB negative. My father’s dog tags, from the military, indicate that he was O positive.

    From photographs and time sequences for conception, there are doubts that the man I called father is really my blood father. The disparities in physical characteristics, the manner in which we were treated growing up, and our psychological makeup are extremely distinct. My brother was the first born, and has blood type O negative. I am O positive.

    I am now 71 years old and only wish to verify if or not I was the love child of another second lieutenant while my father was in amphiibious training for the Normandy Invasion on D-Day.

    I have asked my brother if he talked about it with my mother since I left the house at 18 years of age and never returned until 20+ years later. He and my mother were best buddies and often palled around together. He says she never spoke of it. When I bring up the subject of how different we are in every aspect of our lives (physio, psychological, upbringing, etc.), he simply dismisses the subject with, “What does it matter?”

    Although I am an engineer, I have difficulty understanding the biology of blood types and Rh factors. Biology was not my forte in college!

    Thank you,

    Larry Richardson
    Los Lunas, NM

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    • Lucy

      Hi
      I am not an expert, but from what I have been reading about blood types, I think your mother was mistaken in saying she was AB negative…
      To have O children she would have to have an O in her genes, for example she would have to have been AO or BO.
      An AB mother would produce either an A or B baby I think…
      I could be wrong but this is my understanding.
      Maybe you could check this specific fact out.
      Lucy

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    • Sam

      Larry, perhaps I can hep put you mind at ease. I have the exact scenario in my family, and this is how a geneticist explained it to me. “This reminds me of a case in Japan. There an AB man and his O wife had an O child. Lots of research later, the researchers showed that he had his A and B genes stuck together on one chromosome and a “blank” spot on the other. What that means is that he could either pass AB to his kids or O and so with an O wife, he could only have O and AB kids.Another possibility is that dad has a really rare blood type called Bombay. These folks look O but genetically can be any blood type. If this were the case, then you and your brother might have the same blood type. Like I said, this is extremely rare.”

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  252. Rock

    My blood type is A negative my father is O rh positive what can my moms blood type can be and please what if both my parents have O positive are they really my parents please answer I am worry about:!?

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  253. Connie Jones

    Hi Doc: My brother and I are adopted and have been told that we are both from the same mother. Birth mother says, No, that she miscarried a boy before she had me out of wedlock… Long story..
    My question to you is..Can a sibling with A+ blood type and the other sibling with O- (Me)…be related?
    Just curious. Thank you..

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  254. Bridget

    i am confused …OK i have O- blood type and my Husband thinks his is A+(from blood test he did back in high school ).. we have 5 children all are O- so is that possible or is he really A-

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    • KIMBERLY ROBBINS

      I am trying to figure out the same thing during this pregnancy because I am trying to avoid getting a rhogam shot if my husband is positive, however, my husband is not sure whether he is positive or negative. I am O negative and my husband is A (something). All my kids (3 of them) are O negative as well.

      If your husband is positive, he could be ” ++ ” or “+ – ” which would still make him positive. If you are negative, then you are ” – – ” So, when you you do the calculations, your kids have the possibility of coming up “AO” which is simply “A”….OR….”OO” which is simply O. This is because you both pass on one letter to the child. For your kids to be O and your husband to be A, he HAS to be “AO”.

      As for the RH factor, he HAS to be “+ – ” so he can pass on a negative to the kids just like you. That would allow them to be O negative. So, yes, it is possible for him to be positive.

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      • Rajesh

        Docter I am simply verifing my blood group is O positive and wife blood group is B positive but my baby is b positive it is possible sir

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  255. san

    My blood group is O+. My wife’s blood group is B. My son’s blood group is AB. Is that possible?

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  256. sravanthi

    Both of my parents are B positive and I am B negative. This is possible?

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  257. Freda Arthand

    My daughter and I have the same blood type — O positive. Her dad (I think that’s he dad) has AB. We did a swab test and it was suppose to be her dad. However the guy I was with also had O positive blood. Could it be possible that the other guy is the father to my daughter? The one with ) Positive blood?

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  258. JC

    My sister is an O blood type. My mother is AB and my father is O. Is that even possible? Are they my parents or am i adopted?

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  259. patrick clancy

    if you have two parents one with o- blood and one with o+ positive blood is it possible to have two siblings with O negative blood and the other with o+positive

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    • Henk

      Yes, this is possible. Rhesus positive can have gene type ++ or +-. If one of your parents have +- and produce a child with a — gene type (Rhesus D negative; see explanation by Dr Greene), siblings can have both +- (Rhesus D positive) and/or — (Rhesus D negative).

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  260. Lisa

    Both my parents are O, my two siblings are O, but I am A. Is this possible?

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    • April

      No, two O make O

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  261. Ann

    What does it means if the baby have a A+blood type, and the mother is o and the father is o. A little confuse. Can you give me the answer
    Thank you

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    • Migdalia

      Doctor I don’t understand why my child came out with A+ blood type but me and my spouse have O+… Please help

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  262. mical

    Dear Dr….me and my wife are A positive …what shall my children blood group. ? I really like to know. .Thanks

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  263. Alexis

    I’m becoming concerned whether or not my parents are my biological parents. Everyone in my family has O++ blood and I’m O-, plus I don’t resemble any family members. I don’t know what to do?

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  264. Gyasi Dennis

    Both my parents have type O,but i have type B-,please is it normal?

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  265. Ashley Chambers

    Okay i need help understanding i am not sure of mine or my parents blood types i do know my sister is o begative with rh negative does this mean i too will be rh negative.? My next question is i have been cleared from a dr saying i have no fertility issues as has my husband but in 8 years were not parents yet is it possible that our blood types could be not compativ
    ble causeing us not to be able to get pregnant?

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  266. TheOtherRosie

    That sounds simple enough. Parents each have 2 genes that determine the blood type of their offspring. Each parent shares only 1 of their 2 genes with their offspring. The dominate gene determines the offspring’s blood type. I’ve been out of college for a long time. I didn’t have much science in college, but I’m making up for it now. Enjoyed your article very much. Genetics is so very interesting. Thank you for sharing. : )

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  267. now confused over bloodtyping

    ok, my first husband was O+ and so am I , our child is O-, my second husband is A+, me O+ and our child is A-… how is this?

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    • kim

      You = O + – (positive is the dominant gene and negative recessive)

      First husband same.

      You both gave your recessive gene to your child.

      Second husband will have to be A+ –

      Your second child will be AO blood type (A being the dominant and O recessive) and like your first husband you both gave your recessive – to your child.

      Hope this helps.

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  268. Jacqueline Gardiner

    I remember talking with ny genetics instructor about this. Both my parents are rh positive. My Dad had issue believing I was his because I’m rh negative. Initially she said no, its not possible for two positives to have a negative. My heart fell through my stomach. As I turned to walk away she yelled “wait a minute!” I learned that one of them carries the recessive gene. Pretty cool stuff.

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  269. Ravi Bhatia

    my son is ab positive , me & my wife are both b positive. is it possible?

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    • Cody

      I don’t think so. To have a b type blood you have to have two genes that are either BB or Bo. If two people make a baby that have B type blood it is either BB+BB or Bo+BB or BB+Bo or Bo +Bo. There is no A in the mix to make AB child.

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  270. kat

    Okay, my parents are rh+ both of them. what would i be?

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  271. april

    My blood type is B- HR what would my parents blood types be?
    I have 2 kids and they both have AB+, I was given the rhogam shot during and after both my
    prengnecies, why?

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  272. Chris

    Please help…. I’m confused,.. My blood type is B positive and my mothers is A negative, is this possible ?

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    • Michelle Patterson

      Yes. Your father must have been B positive. Everyone actually has TWO letters (one from each parent) and TWO Rh signs. So since you are B+ you are either BO++ or BO+- (BB++ or BB + – would also be type B+ but that can’t be you, because of your mother she had no B to give you or it would show in her blood type. ) Your mother, being A- is actually either AO– or AA– She could have given you the O. Obviously she didnt give you a B, which is why you are BO not BB.) If she had given you the A you would be type AB. So she gave you the O. She definitely gave you the – since she only has – – . So she gave you O – and your father must have given you B+ which means you are BO+- which would be interpreted as type B+

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  273. anne

    helloo,i had a question pls kindly give me an answer .Is it normal that the father ,mother ,and a daughter had same blood types?coz one of my friend family they had all O POSITIVE blood types.

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  274. Emma Lane Davis

    i am in my first pregnancy and my blood type is A- and i have Rh- blood yet my mother has A+ and my Dad has O+ and they are both Rh+. my dr tested my blood thats how i know i’m A- and Rh-. but i don’t understand how this is my blood type and my parents are both positive.

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    • Cody

      For you to have A- blood your parents would both have to have receive Rh-. So your mom could have AA+- or Ao+- and your dad would have oo+- .

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  275. jayson

    hi my parents are both os and i’m ab are they my really parents?

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    • Marisol Torres

      I am a mom that has O- and my husband has O+, both of the kids that I gave birth to are AB+ Even though teachers have asked our kids if they were adopted, my kids know they were not adopted. So it is possible! I guess rare, but possible ;)

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      • jayson

        thank you :)

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        • Marisol Torres

          You are welcome!

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  276. Julie Balfour

    My mum is 0+ I am 0- what blood type could my father be?

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    • Kezia Elizabeth

      B, A or O positive or negative

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  277. Joanne Jackson

    My mother is B I don’t. Know positve or negative my dad is a postive but I always thought my step dad which is o postive was my dad is it possible?

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  278. Heather Hylemon

    I have a question both my parents are o blood type but im a+ an my sister is o as well how is that possible

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  279. Stephen Maria Jarrells

    My dad is an O- my mom is an O+ but I am absolutely B- Rh-…does anyone have an answer? My mom refuses to talk & unsure what hospital i was born my dad says he’s my dad and dont mind a blood test. Plz help

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  280. lorraine wallace

    I am o negative reh both my parents are b+ how is this possibly. ???

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    • Cody

      O and Rh- are recessive genes. Even if someone has them it will not show in their blood type unless they have both of them. So your parents would have to be Bo+- for you to be oo– which is O-.

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  281. Jannette Davidson

    Both my parents are O+, so are all my siblings. I am A+ and my mother swears she never had an affair. I also have very dark skin, no widow peak, and unattached earlobes. Please figure that one out.

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    • Here is more information for you from Dr. Greene –http://www.drgreene.com/unders… One thing to to consider, your blood type could be an error. Before you go any further, consider having your blood type re-tested.

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      • Jannette Davidson

        I am sure my blood type is correct. I don’t think the U.S. Army, the V.A. hospital and all the times I have donated blood could be wrong. We all know out blood type from getting tested when my grandpa and step dad needed to find a match for kidney disease. From what I gather there is a thing called a genetic mutation, can this be the cause?

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        • I don’t know if it could be genetic mutation. That’s a great question. Does anyone else here know?

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          • R Quispe

            According to the following website there is still a very very small possibility of genetic mutation

            http://genetics.thetech.org/ask/ask181

            However, if you are still unsure, only a DNA test will give you peace of mind.

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  282. desteny

    I have a question my sister had her period on novrmber 8 on the 14 she have relationship with one man on december 11 she was in another relation with someone else in january she found out she was pregnant acording to the doctor she consive on december 27 and her due date september 19 she had the baby premature she is A positive the father is Rh o positive and the baby is o positive can that happen

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  283. april

    Hi there,
    Me and my sister are 1yr. and exactly 18 days apart same mom and dad. We have blood type RH O negative and we both have to take the RohGam shot. Now I was told by an RN that it’s impossible for us to be from the same parents and have this blood type. That only one child will come out with RH O negative. Is this true???

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  284. Me Trost

    Question: I am Blood Type O+ and my Brother is Type A+. What Blood Type combination(s) would our parents (RIP) have to of had for me (Sister) to be O+ and Brother to be A+?

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  285. Noelito Zipagan Glorial

    pls answer, how about parents with O type, and the child is A??is this possible??pls answer

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  286. Rose

    I am A-, my sister is A+, my brother is O+………is it possible that we have the same mother and father? There are doubts that we have the same father. We think we have the same mother but our father is the ?

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  287. Cheryl Boisoneault

    I am RH-A negative . My Mom is O positive and my Dad is B positive …How did this happen?

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  288. rj

    hi good eve. i have a question regarding my blood type my parent is A blood type me is B negative is it really my parent

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  289. Mohammed Mubeen

    Hi, i hav a question that my blood group is AB and Rh positive and my wife is O+ and Rh negative so what will be the result for this…?? and if she has O= and Rh positive then what will be the result…??????

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  290. Miranda Decker

    Here’s an odd one. My parents are both o+, so is my sister… I am A negative. So… I’m really starting to wonder how this would be possible….

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    • Cheryl Boisoneault

      Same here did you get an answer? my parents are positive to and both my brothers as well None have A blood…Or are they negative..my blood type is A negative RH ? I would love to know how this happened

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    • Mela

      My parents are both 0 + , me and my brother are 0 – . And its totally fine because 0+parents can only give birth to babies with 0+ or 0 – blood type. In our case it happened to be 0- . :)

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    • Charla Satterwhite

      Miranda, did you ever find the answer to your question? Because I need to know the same thing.

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      • mariya

        My blood group is a positive and my husband o positive. But our son o negative. Is it possible. ?

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        • Mariane

          I am A+ and my husband is O+ and our son is O- too. This is possible so don’t worry.

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  291. Miss Jennie

    My dad belongs to B type blood and my mom belongs to O type blood, whereas my brother belongs my dad’s blood type but how come my blood group is A positive?

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  292. Peggy Robinson

    Can a RH Negative and A O Have a A positive Child?

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  293. Peggy Robinson

    Can A RH Negative And a O Have an A positive child?

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  294. Miriam LuvEtte Saucedo

    My parents are both B+ … Why am i A+?

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    • Subasis Mishra

      Is it possible that baby having A+ve if both parents have B+Ve blood group?

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  295. Nean

    my mother has 0 Negative RH blood group – bit of confusion as my fathers dog tags of 1947 simply have 04 blood type…he told me they both have RH O Negative…and his is rare – I am O Positive – born in 1958 in an out back town in the Northern Territory where blood transfusions for the baby be non existent…very confused…my younger brother definitely theirs RH factor child severe anger issues, learning difficulties speech, tactile…I am 55…my parents told me I was adopted they are both in their late 80’s and with cancer I am their carer mum is now in full time care…could you please tell me is it possible for two O negative Rh blood groups to have children…my brother is fine now but was an out of control toddler and child and violent…thanks so much they do not wish to discuss my adoption which is fair enough.

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  296. island boy

    Hello, I have a question. Can both parents with type O blood produce a type A+ child? Both my parents are type O and i am type A+. Switches in the hospital can happen to where i am coming from. Please help!

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    • Huckle_Cat

      I think he answered this question in the paragraph where he says, “if two parents both have type O blood, all of their children will have type O blood.” That is because they can only pass on a type O gene to their children.

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    • Jaclyn Elaine

      My parents are both o+, and me and my twin sister are ab+ so we have been wondering this as well. There is no question of paternity or switching at birth as we are splitting images of our parents, and we are pretty confident in the results of the blood tests

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    • Michelle Patterson

      No. If both of your parents are type 0, they could NOT produce a type A child.
      It is possible that either one of the three of you is incorrect about your blood type. It is still possible they are both your parents if either of the three of you is incorrect about your blood type. Or possibly one of them is not your parent. If you are 100% certain you are type A then you HAD to get that A from one of your biological parents, either your father or mother. Your mother could be type O, but then your father would have to be type A, or vice versa

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