Blood Types 102: The Role of A, B, O, and AB Groups In Determining Paternity

Hello Doc, Is there any way of determining the father of a child before it is born?
Jamaica

Bllod Types 102

Dr. Greene’s Answer:

Having a baby is a lifelong responsibility and hopefully an even greater reward — for somebody! As a mother’s belly swells, she knows with deep certainty that the child is hers. Each time the baby moves or kicks, the bond between her and her child grows.

Depending on the situation, the father may be pretty sure that the child is his. For most of history, though, dads have had to rely on circumstantial evidence as the foundation on which to build this crucial relationship. After the baby was born, he could feel more sure he was the dad if the baby looked like him (“He has your feet, Honey!”), but often these early resemblances are at least partially creative imaginations.

In 1901 biologist Karl Landsteiner distinguished between three types of blood — groups A, B, and O. A fourth group — AB — was discovered a year later by another research team. As the inheritance patterns of these blood groups were worked out over the next decades, it became possible to include the use of blood type in determining paternity by excluding some men from being the fathers of some children. For instance, if the parents both have blood type O, then the children must all have blood type O. If a child were to have blood type A, B, or AB, then the presumed father must not be the real father. If the child’s blood type were O, then the presumed father might be the real father — but so might millions of other men.

Using Blood Type in Determining Paternity:Possible and Impossible Situations

Parents’ Blood Types

Possible Children

Impossible Children

A & A

A, O

B, AB

A & B

A, B, AB, O

none

A & AB

A, B, AB

O

A & O

A, O

B, AB

B & B

B, O

A, AB

B & AB

A, B, AB

O

B & O

B, O

A, AB

AB &AB

A, B, AB

O

AB & O

A, B

AB, O

O & O

O

A, B, AB

 

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.

Determining Father Before a Baby is Born

It is also now possible to determine the father before a baby is born. This is done by comparing DNA molecules — our genetic blueprints. To do this you need a blood sample from both the mother and the potential father (testing without the mother’s blood is possible, but more difficult — and more expensive). You also need a small sample of amniotic fluid (the water that the baby is floating in). Less than 1/4 teaspoon is sufficient for the test. The amniotic fluid may be obtained by a process called amniocentesis. This procedure is performed no earlier than 13 weeks into the pregnancy.

A court order or informed consent of all adults involved is required to proceed with paternity testing.

You will need to wait 3 to 4 long weeks for the results. Waiting for these test results can be a very anxious time. Rush orders take 10 to 15 business days, but cost about $500 extra.

Either way, if the test says that a man is not the father, then legally and truly he is not (it can absolutely exclude some men as the father of a certain child). If the test says that he is the father, then he probably is — there is about a 99.8% chance that he is. DNA testing is now legally accepted as able to determine paternity.

There are about one million two hundred eighteen thousand five hundred males in Jamaica (as of 1992). A positive DNA paternity test could limit the potential fathers to only about 2,437 of them (plus 0.2% of the tourists). Only 2 out of 1000 men could possibly be the father. As you can see, a positive paternity test is good evidence, but not an ironclad guarantee.

Paternity Testing

Prenatal paternity testing can be arranged through a company called Genelex, located in Seattle, Washington. They are very helpful, and can be reached at 1.800.523.6487 or healthanddna.com. The test costs $700.

If you wait until after the baby is born, DNA testing can be arranged through most local blood banks (many of which use Genelex). The blood sample can be obtained at birth. Otherwise, the baby should be at least 2 months old, since a fair amount of blood is needed for the test. In my area, this option costs about $600.

I realize that the circumstances that prompt a person to undergo paternity testing are often difficult. I hope that whatever you want turns out to be true. Even more, I hope that whatever turns out to be true becomes something that you learn to want.

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. Zak

    Can the child blood group be B POSITIVE If father has O POSITIVE and mother has A POSITIVE?

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    • That is not considered a possible combination.

      Before jumping to any conclusions, it’s wise to have all three blood types re-checked. It’s not at all unusual for one of the three to be different than what’s reported. There are several reasons for this — error at the lab, mix up of blood samples, error in reporting, error in recording, etc.

      Hope that helps,
      @MsGreene

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  2. Kim

    If moms blood type is o+ and dads is ab+ can the childrens blood types be o+ and b?

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  3. Marlene

    I am B+ and I have believed my husband to have O+. My oldest daughter is a B+ and the youngest is O -. My mother in law is O -. Is it a recessive gene?
    My daughter is under the assumption that her father must be a rh negative.

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  4. Margaret

    My husband is O+ and mine is O+. Can we have children?

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    • Based on those blood types, there is no apparent reason not to try to have children. There are no health risks associated with two people who have the O+ blood having children.

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  5. jb

    If the father is a b or ab positive could he have a o negative child?

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  6. jb

    If the baby is o negative n the mother is o positive what is the father blood type likely to be?

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  7. Randy

    If the pregnant women has rh negative blood. Can a non Invasive paternity test still be properly perform.. the day baby’s DNA is in mother blood while pregnant but if baby is positive and mother is rh negative how would that work? Or it it chromosomes in it not cells….thanks …please answer

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  8. Elizabeth

    If my mother’s blood type O- and mine is B+ what blood type would my father have to have.

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    • If one parent’s blood is O- and the child is B+, the other parent would be B+ or AB+ blood type.

      Hope that helps!
      @MsGreene

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  9. Merlith Fulkerson

    Hello, i have a question and hoping i can get an answers here…. My blood type is A+ my mother is Type B and my father is type O,what does it means? thanks…

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    • Melissa

      That means you need to talk to your Mom… I had the same situation.. I am AB+ and father is O- NOT POSSIBLE!!!

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  10. jen monasque

    hi dr.greene is it possible that my blood type is O+ and my parents has the blood type A+ and AB+?

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    • Hi Jen,

      If one parent is A+ and the other is AB+, each of their children could be A, B, or AB, Rh+ or Rh-. The only blood type their children can not have is O.

      In a situation like yours, it’s wise to have everyone retested before jumping to conclusions. It’s not unusual for one of the parties original blood type to be different than what is reported.

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

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  11. Lisa

    If my brothers blood group is A- and his partners is A- how can the baby be O+

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    • If both parents are A-, there is a 6.25% chance each of their children could have type O blood, but all there children will be Rh-. If one parent is A+ and one is A-, each child would have a 75% chance of having Rh+ blood. It is possible that one of the blood types was in error, reported in error, or remembered incorrectly. Before jumping to any conclusions, it’s wise to have everyone retested.

      Hope that helps,
      @MsGreene

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  12. rod

    my brother is blood type ab and my blood type is o. is that possible that we both have same parents.

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  13. David Duobah

    Hello, l am ‘A’ Negative and l’ve started having children. Still single, not involved with sex yet, l’m 27 years old. What’s the possibility that l’ll have a child?

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  14. Harmony

    Hello, i’m AB but my mom is AS and my dad is AA. I was wondering- how this is possible? (I’m sure my parents are both my biological parents.)

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  15. MAINGA

    Add your message here
    Hi .Doctor i have blood group o- and my wife two be she has blood group A+ is there any difficulty on giving birth for our future child’s if there is what could we do?

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  16. yusuf khan

    hi dr my blood is B+ and my wife is A+ so what is blood type cheldrans can we get

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    • With that combination, your children could be A, B, AB or O and Rh- or Rh+. Basically, this combination doesn’t eliminate any blood type. The type that is most common for a child with one parent who is B+ and the other who is A+, is AB+. But Any type is possible.

      Here’s an interesting article for you on the topic Blood Types 101: An Introduction to ABO Blood Types and the Rh System.

      Hope that helps,
      @MsGreene

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  17. liz

    Can two parents with a negative make a child with o blood type.

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  18. Ami

    Hi
    I am O negative and my mum is AB negative. Is this possible? Also, what must my after be if I am O negative?

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    • Ami

      Father*

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    • If one parent is AB, her children can be A, B, or AB because that parent can only pass along A or B, so no matter what the other parent is, the child will have either an A or a B gene from the parent who is AB.

      Hope that helps,
      @MsGreene

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  19. charlotte

    i am o negative … what possible blood groups could my mum and dad be? i know my mum has a negative group and my dad has a positive one but just not sure which ones exactly

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  20. ankur soni

    If husband has blood group as A+ and wife has O+ then can there be any complications during child birth.?

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    • I wonder if you are worried about Rh incompatibility. This is an issue when the mother has Rh- blood and the father has Rh+ blood. That does not appear to be your situation.

      I hope this helps,
      @MsGreene

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  21. SHIJIL

    My Mother is A positive and My Dad is O positive. . . But my blood group is A negative. can this happen???

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    • Yes. If one parent is A+ and the other is O+ each of their children have a 75% chance being blood group A and a 6.35% being Rh-.

      @MsGreene

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      • Loraina

        I have type A+ and my children’s dad had either A or O +. We have 2daughters that are A -. Our son is o+. Where would the .. A negative come from . Thank you.

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  22. Parkavi

    What will happen if i marry my Mom’s younger brother with same blood group?

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    • Two parents can have the same blood group without issue, but there can be genetic issues when two parents are closely related.

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  23. sunny

    Greetings Dr.
    Is it possible for O positive parents to give birth to O negative child. if yes/no how/why.

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  24. Kelly Ann

    Ok so my mom is ab- my brother is a+ we don’t know what blood type my father is but i assume he’s +. I’m o+ my boys are all o+ which isn’t a surprise since their father is o+ too. I know my mother is my biological mother so can I be one of the rare mutations. And if i do have a rare mutation or whatever do i have to worry about any health issues or greater risks for diseases

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  25. KISHONE.TPM

    sir, my blood is A+ my wife blood is b+ and my child blood is b- ,how come this type blood

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  26. Nina

    Hello,
    I have AB+ blood while my mom has O+. My dad’s not sure of his own blood type. I’ve been doing some research and I keep seeing that it’s impossible for a parent with O to have an AB child. Is this a mutation?
    Thanks!

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  27. Mary

    Hi,
    My mum is B+ and my father is O- but I am a A+ and my twin sister is B+. All of my other siblings are B and O. Is this possible?

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  28. aryan patel

    when father and mother are blood group O positive then child blood is B positive, it is possible or impossible ?

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  29. munna patel

    when father and mother are blood group O positive then child blood is B positive, it is possible or impossible ?

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  30. Jayasri

    my blood group is B positive and I’ ll get married A1 positive blood group person. anything problem in my child

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  31. Tia Patterson

    1. If my mom is AB- and I am B-, is my dad a positive or negative O? I know that he is in the O blood group, but I don’t know if it is positive or negative.

    2. I also have heard that ethnicity factors into the determination of blood type. My mom and dad’s families both are mixed with white, black, and Native American. Since AB- is a rare blood type, does this tell you anything about mom’s heritage?

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    • Hi Tia,

      As I’ve said on this thread many times, I’m not a doctor or a professional scientist. But I find this topic fascinating and am happy to help when I can. I know based on our current understanding of science, if one parent is AB- and a child is B-, the other parent could be A-, B-, AB-, or O-. I don’t have enough background in this topic to address the ethnicity question. Can anyone else on this thread? I think it’s an intriguing question.

      Best,
      @MsGreene

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  32. rameez

    My blood group is O-ve and my lover blood group is A-ve it’s eny problem for our children

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    • Hello Rameez,

      You may have heard that women with Rh- blood can have an issue with their blood being incompatible with their baby’s. Dr. Greene has written about this to another reader: How To Determine and Manage Rh Incompatibility. The problem occurs when the mother is Rh- and the father is Rh+. If untreated the outcome can be very serious so it is worth double checking both your blood types to be sure your partner isn’t Rh+.

      If a woman is Rh- and her partner is Rh+, there are treatments that can be given to prevent (99% effective) issues during pregnancy.

      Best,
      @MsGreene

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  33. munna patel

    when father and mother are blood group O
    positive then child blood is B positive, it is possible ?

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  34. a.razzaq

    Aslam o alikum
    how are you dear?
    please solve mine matter….
    my blood group is b+ve and of my wife is O-ve. yesterday i along with my wife went to l gynecologist. she told we should visit to her clinic for delivery case which is much far from us. in addition she told some complication may occur due to this combination of blood. now i am in little bit suspense. please guide me, can any complications occur in this type of blood combination???????

    and in addition what is about thylosemia cases?
    she

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  35. Cheryl Smith

    I am 39 and my sister is 42. All our lives we have been hearing rumors that our father is not our father. My sister and I both have AB- blood. I read somewhere that BOTH parents must have a negative rh factor to have a child with ab- blood. Is this accurate?

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    • ann

      If the father is AB- and the mother is O+ can the child be B+?

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      • Yes, this is a possible combination. There is a 50% chance that each child of parents who are AB- and O+ will be type A and 50% will be type B. 75% will be Rh+ and 25% will be Rh-.

        Hope that helps,
        @MsGreene

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  36. naresh nayak

    if both parents are blood group O
    positive ,
    and my child is B positive, it’s
    possible ?

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    • This is not considered a possible outcome. DNA testing is much more sensitive than blood type testing. You might consider that if you’re concerned.

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      • naresh nayak

        sir, plz tell me – what i do?

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        • naresh nayak

          How much chance of having a baby is not mine?

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  37. Dave

    My mother’s blood type is AB, while my father’s was A+, yet I have blood type O-. How does this occur? Our blood types were accurate. In fact, my father was a phlebotomist. My high school biology teacher also tested us and found this accurate. He said it can occur, but never explained how.

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  38. mother

    I am O Negative and my daughter is O Postive.. her father doesn’t know his so what could her father’s blood type be?

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    • If one parent is O- and his or her child has O+ blood, the other parent can have A+, B+ or O+ blood.

      Best,
      @MsGreene

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  39. rahul raj

    If both parents have blood group ab+ can they have their child with blood group O+ or O- ?

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    • Type AB+ is fairly rare. Only 3% of people in the US are AB+. AB- is even rarer, with 1% of US people. Individuals with AB+ blood are considered a universal plasma donors.

      Two parents with AB+ blood can have children with A+, A-, B+, B-, AB+ or AB- blood types. O+ and O- are not considered possible blood types for children of two AB+ parents.

      If your parents give blood, they will have their blood types confirmed.

      Hope that helps,
      @MsGreene

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  40. Tina

    I am O- and my daughter is O+ and my son is A+ do they both have the same father? Is it possible?

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    • It is possible. The father would have to have A+ blood type.

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  41. Dawn

    If dad is o+ daughter is o+ what could mom be? Sibling to mom is b+ if that helps

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    • If one parent is O+ and his or her child is O+, the other parent could be A+, B+ or O+.

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  42. naresh nayak

    if both parents are blood group O positive ,
    and my child is B positive, it’s possible ?

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  43. Nichole Warner

    So according to this it’s impossible that my Father is really my Father. Anyone know if there is a way to look up my parents blood types to be sure I am remembering correctly what they told me they were as my Dad is deceased

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    • Nichole,

      It’s very common for people to remember a blood type incorrectly. It’s not rare for it to be recorded incorrectly. Without your father being able to provide a current blood sample, you may never know for sure, but you may be able to get access to his medical records depending on how long he has been deceased. Those records may or may not contain his blood type.

      Best of luck,
      @MsGreene

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  44. Scotti Brown

    I know my mom is A+ and I am O negative, so what does that make my dad? Because charts I have looked up says that he is most likely to be either A, B, or O

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  45. Tracy

    Can a A-mother and an B- father produce an B+ child?

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    • According to the current genetic thinking, this is not a possible combination, because two Rh- parents can not have an Rh+ child.

      It is not uncommon for testing of one of the three parties to be incorrect or reported incorrectly. Additionally, what we “know” about science changes every day.

      DNA paternity testing is considered to be highly reliable.

      Hope that helps.
      @MsGreene
      Executive Producer and Co-Founder DrGreene.com (not a doctor)

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  46. Michele

    My mothers blood type was a negative, fathers o positive. Mine and 2 brothers blood type is o positive. Another brother type is ab negative. Does that mean he has a different father?

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  47. Saonly mukherjee

    Father a+VE mother b-ve is it possible for son to have b+ve.

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  48. Name

    If the dad is A- and the mom is b+ would it make since for the son to be Ab+ it makes since to me but the father seems to think it’s not possible.

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    • There is a 56.25% chance that each child of a parent who has type A blood and a parent who has type B blood will be AB. There is a 75% chance that a child of a parent who is Rh- and a parent who is Rh+ will have Rh+ blood.

      Based on the article above, does that make sense to you?

      Best,
      @MsGreene

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  49. George

    Hello I have a question my mother is o+ and father ab+ my sister is b+ and I’m ab+ is there a possibility that my father isn’t my biological father ?? And if we take a test and he is would I be the first case that the chart would have been proven wrong

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    • Blood types can not prove paternity. They are very general. DNA results are used for specific paternity testing. However in the scenario above (one parent is O+ one is AB+) the charts indicate each of their children have a 50% chance of being A, a 50% chance of being B and 0% chance of being AB. Each child has a 93.75% chance of being Rh+.

      As you indicate, the charts may be wrong.

      There are several reasons, errors in testing, errors in reporting, errors in memory of the people who were told their blood types in the past, our science is incomplete.

      I don’t know if you would be the first person to prove the charts wrong or not, but even if you aren’t, keep in mind, tests are flawed and we learn new things about genetics every day.

      Hope that helps,
      @MsGreene

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  50. Mary Duckworth

    Hello! My daughter have blood type “O” and me is bloody type “O” as well but my husband have a blood type O+ it can be possible that he is not the real father?

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  51. Lorquenzia

    Hi I’m the mother and Im a O+ And my son is a O+ but I don’t know what is the Dad blood type can you help me find out what is the blood type of the father may be.

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  52. tasha

    Can both parents be A+ and child be AB

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  53. Darla

    My son is o- . His girfriend just birthed her 3rd live child, 5 total. She is o+. She did not get rogaine shots. Baby is o+. Is this possible? Urgent.

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    • AK

      Yes there is 50 % chance of the offspring of parents who are positive and negative to be positive.

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  54. Deepa

    My group is b positive my husband group is o negative my child group is a2 positive. Is it possible

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    • Deepa

      My group is b positive my husband blood group is o negative my daughter blood group is a2 positive. Is it possible sir

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    • Deepa

      Sir my blood group is b positive and my husband blood group is o negative. My daughter blood group is a2 positive. Why it happens

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  55. Israel Garcia

    I did not have my parents blood type but my dad’s sister did

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    • deedea

      Hi. I’m a daughter with a+ dad a+ my brother a+ my mom is D. What does this mean?

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  56. Md. Sabbir Ahmed

    If father’s blood group is O+ and Mother’s is A+. Will there be any problem with their child?

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    • Patrick

      no there will not be a problem with the child

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      • Joanie

        My dad is AB+ and mum is O neg and I’m O positive is this possible

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  57. Sadhana

    My husband blood group is O+ve and my is b-ve. There is any complications to get pregnancy? What will my child blood group.? Plez help me out…

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    • AK

      It can be B+ve, B negative, O positive or O negative.

      You need to get injection rhogram in case your offspring is Rh +ve or it will complicate your next pregnancy.

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    • ilayaraja

      any problem

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  58. Holly

    Can a male O- male blood type have a child(ren) with an AB+ female?

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    • Hugo

      Based on what I have read the probability is zero. On the other hand my mother is AB+ and swears her father was O-. They are mirror images so no doubt he is the father and I look just like my grandfather too but only God knows..

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  59. harish

    My blood group is A+ and my wife blood group is AB+ . what could be my baby blood group?

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    • Children of an A+ and AB+ parent could be A +/-, B +/- or AB +/-.

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  60. khurram parvez

    HI.. iam 35 yrs old and i do not get child since my marrige (2.5) yrs. i checked that my sperms count is nil……so plz.. advice me what to do.

    thanks.( india)

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    • AK

      Adoption is a good alternative if you cant have kids

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  61. Sharla

    Hello Dr.green I’m in the need of help to get a DNA paternity test while pregnant can you only use the mothers blood ? just the blood and not the fluid? …or do you need to have the fluid that the baby floating in .. to see who the father is? I know I need his DNA ? And is it possible to have the results in 3 to 4 days

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  62. Andy

    Hello Dr.
    My friend she is a female….. her father blood group is A( ve) and her mother A(-ve) & her blood grp is AB
    is it possible?

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  63. IVF Mom

    Hello..

    2 years ago my husband and I began IVF treatment and got pregnant with our now 15 month beautiful baby boys.. My husband is O+ and I am O-.. When we were in the hospital after having the boys, we were told their blood types were A+ for both, it didn’t make lots of sense to me at the time (without ever having read on the subject) but I didn’t dwell on it.. Also, the doctor said to retest the boys when they were older since markers sometimes evolve with age.. That was it.. Now my husband and I will probably get divorced and I want to know if there was a possibility of an error during IVF procedures, since I am afraid one of us may not be biological parents.. I know if it is me he will be more on the offense to take the kids, and if it is him he won’t even try.. I love my babies with all my heart regardless.. Anyway, how can our babies be A+ and still be ours? Or is this a definitive proof that there was gamet error during IVF??

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    • Shirley Cooper

      They may be both of yours! I gave birth to three beautiful children that have A blood types. Their father and I are both type O. A paternity test was done and all three are ours. Sometimes, although it is very rare, mutations take place and babies can have a different blood type than that of their parents.

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  64. Mike

    Hello I am A pos and the girl I have slept with is A pos. We slept together at the beginning of the month and used protection and a week later she had a period but the slept with another man who is O negative towards the end of the month they had unprotected sex. But got pregnant towards the beginning of the next month and the baby came out O positive she says I might be the father is this true?

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    • AK

      A+ and A+ can give O+
      A+ and O- can also give O+
      So chances are it can be either’s.

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  65. Aloh

    Hi my father is AB+ he was hospitalized and he undergo blood transfusion when i tried to replace the used blood form the hospital i was shocked that i have blood type O+ my father is AB+ why is it my blood type is O+.does this mean that my father is not my biological father.

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  66. ciara

    If the mother has o+ and the father has B+ and they have twins, one twin has o+ and the other has A I’m not sure if it’s A+ or – would he be the father

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    • If one parent is O+ and the other is B+, each of their children will have an 18.75% chance of being blood group A or B, a 56.25% chance of being blood group AB, and a 6.25% chance of being blood group O. Each child will have a 93.75% chance of being Rh+ and a 6.25% chance of being Rh-.

      What does this mean for you? First, in the example above, the twins can not be identical because they have different blood types. Second, you can not rule out a possible father of these two fraternal twins because he has B+ blood. A DNA test is typically used to determine paternity.

      Hope that helps,
      @MsGreene

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  67. Rita Amoo Gottfried

    please I won’t to know if both parents
    are o positive, how healthy is their children

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    • If both parent have type O+ blood, their blood type won’t have a negative impact on the health of their baby. There are many other factors that can make a difference in the baby’s health, so it is impossible to determine the health outcome of their children, but blood type incompatibility should not be an issue.

      Best,
      @MsGreene
      Mother & Co-founder of DrGreene.com

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  68. Michael

    Hello DR,
    My blood type is ab+ and my wife is O+ we recently had a son who is ab- but I keep hearing this is impossible?

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    • If one parent’s blood type is AB+ and his or her child is AB-, the other parent would need to be A+, B+ or AB+.

      In your case, it sounds like the three of you need to be re-tested.

      @MsGreene

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    • Lyrika

      My information/situation is identical to that described by Michael. I am annoyed, offended and suspicious of the “doctor’s” response, as it is dismissive and megalomaniacal, suggesting that ANY human knows without question what is and is not possible in the realm of human genetics. In this day and age, when any informed person must realize that anything is possible and that almost nothing is in actuality explained or understood by medicine or science, it’s essentially an exercise in futility to hope for real answers from adjutants of our current, highly suspect system of dis/misinformation. The AB- blood type is allegedly the rarest on Earth, and children with this blood type ARE being born to parents without rh- blood. That is fact. I tend to think the claims of so called “medical professionals” indicate either they are not willing to admit they don’t have all the answers, or they are lying for reasons we can only, at this stage, speculate about. I would urge Michael, and anyone else in this situation to exercise caution and patience…science and medicine have a long history of hubris and inhumanity, and are part of a system designed to profit from our pain and illness. The answers we seek will likely not come from this sector. If you love your child, then love your child. Make his/her care and protection your priority.

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      • Hi Lyrika,

        First, thank you for your very apt response. We know so little and are finding out more all the time.

        I do need to correct you on one point — I am NOT a doctor. I do respond often on this post and I try to make it clear that I am a mom, an interested citizen, a casual scientist, but NOT an authority.

        I hope you and Michael will accept my apology if I did not make that clear.

        In re-reading my response, perhaps I should have qualified it with “as far as we know at this time”. So much of what we know is evolving.

        Best,
        Cheryl Greene
        Mom, co-founder DrGreene.com, NOT a doctor

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      • Lyrika

        Hello, Cheryl, and thank you for your reply and clarification. That you describe yourself as a ‘casual scientist’ actually gives me some hope that your mind (and heart, more significantly) is open to possibilities, and that you are not subject to the controls and threats under which mainstream doctors and scientists too often must operate. After my post, I visited a site dedicated to current genetic research and was happily surprised by the statement that nothing in genetic research is black and white, and researchers are daily discovering exceptions to “rules”. I spent hours there and will return to do more reading, it is a vast and fascinating subject, and truly demands an open mind and willingness to question all we think we know. Ultimately, I feel, when it comes to parenting, the only essential choice is love. I think to hang our willingness to do so upon a theory touted as fact is a huge error in judgment, and can have far reaching and tragic results for both parents and children. Please, people, invest in your own learning process, do not consider the opinion of anyone, no matter how learned they might claim or appear to be, as the final word on any subject…everyone walks their own path and has their own agenda. We are responsible for our own path, and it’s been my experience that it is not only difficult but dangerous to walk in the dark, or with our eyes closed.

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        • Lyrika

          Sorry for this blurb, it should have been part of my previous post. For those who want to investigate blood types and/or genetic research in general, I think it’s a pretty godd place to start: http://genetics.thetech.org/genetic-categories/blood-types
          Also I would like to say to Cheryl, no apology is necessary, not to me. You are trying to help people, and so very many simply do not bother. I apologise to you, for my assumptions. Be well, love light and truth to you and yours.

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  69. Victoria Andreenkova, Dublin.

    I wish to know what my sons father blood group type is, (1) Mother = B rh negative, (2) Child = AB positive.

    What would be then the fathers blood group type?

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    • In this scenario, the second parent could be A+ or AB+.

      Hope that helps.

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      • Victoria Andreenkova, Dublin.

        Thank you doc, yes it could be only A+ or AB+ I reckon its A+ as AB+ is relatively a rare type, I think only 4 percent of the world population has that type. I am in a paternity dispute whereby the father is denying that he is the father of my son, can I request his blood type so it will be obvious to the judge that he is the father, I am afraid that he might fraud with the DNA process by letting someone else go for the paternity testing. In the event that the DNA results come back negative I then can tell the judge that my son shares same type blood group so that the judge can force the father to reveal his blood group would you think that this can reveal that he is the dad as AB+ would be a very rare blood type, I am not too sure if A+ is?

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  70. Egbodofo mary

    Im AA and my husband is AS, we have a son with AC hw is that possible?

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  71. Appiah Ebenezer

    Please I want to know if the the father of a child is O nagative and the mother is O positive how healthy will thier children be?

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    • There are many factors that determine the health of a baby, but I’m guessing you’ve heard something about blood type incompatibility.

      Typically this is not an issue with a first pregnancy, but it can be a problem with subsequent pregnancies. It is wise to discuss this with your doctor as there are treatments available. It’s great to bring this up as soon as you can, even before you become pregnant.

      Hope that helps,
      @MsGreene

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  72. kenji prollo

    My mother’s blood type is o, and my father is AB. what is my possible blood type doc? and for my brother. thank you

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    • The children of an O parent and an AB parent will be either A or B.

      Hope that answers your question.

      @MsGreene

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  73. Jonz

    Hello…I am A+ and I have one son who is O+ and another son who is A- by the same person. What is the father’s “possible” blood type?

    Father’s mother is AB+
    My mom is A+

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    • Interestingly those blood types don’t narrow the possibilities down much.

      If one parent is A+ and has two children, who have the same parents, and the children are O+ and A-, the other parent could be A+, B+ or O+.

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  74. anupam

    I am O+ , my wife A negative , my first baby A+ , i dont no inj Anti D given or not at time of first delivary , we want a 2nd baby , what treatment is requir ?

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  75. Isaac

    Good morning Dr. Please, i wanted to know if my gene is B+ and my girlfriend is also B+ can we get marriage and what will be the r results of when she become pregnant till the baby come out. I am really worried and i really we really love ourselves, so advise us of what will do to protect the baby when she come pregnant too.

    Thanks Dr.

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  76. karun

    Father with AB -ve and mother with O+ve . What are the precautions to be taken while pregnancy?

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    • Discuss this with your Ob. Typically there is no issue with first pregnancy, but your Ob will discuss your options with you. It’s smart to bring this up before getting pregnant or as early as you can.

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  77. anna

    hello…
    a mother is O positive.. husband is A positive
    our baby born is A negative… how is it possible
    help…

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    • The children of an O+ parent and and A+ parent have a 6.25% of having Rh- blood. For a full explanation see Dr. Greene’s Q&A Blood Types 101.

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  78. Shakia

    My boyfriend is B+ and I’m AB- would this be a cause for concern or are we okay? He’s very concerned with genotype but I just want to know if our RH factors would clash and cause issues?

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    • Typically there is no issue with a first pregnancy, but you should discuss this with your ObGyn. It’s great to bring this up as soon as you can, even before you become pregnant.

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  79. rafiu

    i am o+ my girlfriend is o and he gave birth to a child claiming that i am the biological father and the child blood group is B- how is it possible that i am the father can u please enlighten me more please.

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    • I’m sorry, I want to make sure I am following your question. Are you saying:
      – You are male and have O+ blood.
      – Your girlfriend has O blood type, but you don’t know + or -.
      – She is claiming you are the father of her baby.
      – The baby is B-.

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  80. cherry

    If I am B- and my husband is b+ are there chances of complication in pregnancy also is it difficult to conceive if my husband is 35 +

    thanks

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    • This is an important topic to bring up with your ObGyn. She will work with you to make sure you have the treatment you need before there is an issue. It is wise to discuss this with her before you conceive. It’s not necessary, but wise.

      The age of both parents can influence infertility. In general it’s easier for younger people to conceive, but there are many examples of older (much older than 35) people conceiving without problem.

      Hope this helps,
      @MsGreene

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  81. marriage4me

    Female blood group is O+ which blood groups (male) matching for marriage? kindly explain

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  82. Tayden Dalley

    Hi, Sir. My wife and I at both O- and she is rh- we were wondering if we would come across any issues being that were both o-.

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  83. sana

    Me having o positive and my husbund O negative now im pregnant 9 weeks any problem yo child…

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    • Laxman

      Hi Doc,
      My wife is o+ve and i am o -ve . is there any risk in child?

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  84. Esther owusua

    Dr can A+ n AB- give birth?

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  85. Noon

    Hi Dr;
    If my both father and mother having O+ can I have an O- ?

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  86. ANY

    IF MY WIFE IS O+ AND I AM A+WHAT WILL OUR CHILDREN BE IRRESPECTIVE OF NUMBER

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    • The children of parents who are O+ and A+ can be either A or O and either + or -. The highest likelihood is A+, but all the other combinations are possible.

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  87. shanie hill

    I just want to know if my husband is A+ and I am B- what will the childrens blood group be.

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

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      • Balaji

        If Father is A negative and Mother is AB Positive what will be the Child’s blood group combinations with RH factor

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        • If one parent is A- and the other is AB+ their children could be A, B, or AB and + or -.

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  88. M.M.S

    Dear sir!

    My brother’s blood group is B+ and his wife also has the same blood group B+ve. They have three children. All the children have the same blood group B+ve. The 1st one child is normal while the other two children are abnormal. What would be cause of abnormality? Is it due to blood group incompatibility or would be any other cause?

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    • If both parents have the same blood group as the children, there shouldn’t be a blood group incompatibility.

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  89. Ronnie

    Myself , my full sibling brother and my mum are all o+ we do not know our fathers blood group (DECEASED).Is it possible we have a half sibling sister who is AB-? We do not know her mothers blood group

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    • In the scenario you mentioned, it is possible. Here’s one way it could work (NOTE: there are a lot of assumptions in this scenario – it’s just an example) —

      One parent is O+ and one parent is A- or B-. Each of their children would have a 25% chance of being O+.
      One parent is AB- and one parent is A- or B-. Each of their children would have a 37.5% chance of being AB and a 100% chance of being -.

      This does not mean you have a half sibling. But your known blood groups do not rule it out.

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  90. Ronnie

    Hi myself my full sibling brother and my mum are all o+ . I have a possible half sibling by my father who is AB- (. we do not know our fathers blood group ) . Would it be possible that we are half siblings?

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  91. M.M.S

    Hy sir!
    If a blood type O+ve man married to O+ve woman. Is There any issue of diseases of abnormalities in childs.

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    • This blood type combination does not cause any health issues in the child.

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  92. Emily

    I am O+ and my husband is B-. Would that cause for any issues for our future children?

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  93. April

    I an O+ and my husband is O+, our child is O+, is there any other combination that would make an O+ baby?

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    • If one parent is O+ and the child is O+ the other parent could be A+, B+ or O+. Does that answer your question?

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      • Ridhi Bhatnagar

        Dr. my blood group is O+ and my husband blood group is also O+ but my son blood group is B+ is this possible ?

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        • This is not a “possible combination”. But as Dr. Greene points out, there are rare genetic mutations.

          It would be smart to have all your blood types retested. If they all come back the same, a paternity test could give you further information.

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          • Maritza

            Dr I have the sane situation mom and dad have 0+ and our son ia B+ … And Im 100% sure that my husband is the father of my son… Do I need to worry?

            Added:
          • It would be wise to have all three blood types re-tested. It’s not unusual for one of them to be reported in error.

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        • Mamerto

          Hi Doctor. What blood types of parents that produce an O blood type

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          • The parents of an O child could be A, B, or O, but not AB. Examples:
            A & A
            B & B
            A & B
            A & O
            B & O
            O & O

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  94. Mike

    I’m the father of 3 children & not one of them have my blood type, as a matter of fact my son and both daughters match my wife’s blood type. Is that possible? Mike

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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 A+ and a father was O+ each of their children would have a 75% chance of being type O and a 93.75% 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. Does that make sense?

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  95. Anna Wepener

    My blood group is O+ and my husband is A+, can we have a child that is O-?

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    • O- is one possible outcome if one parent is O+ and one is A+.

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  96. Kathleen

    I was told that my newborn is A+, my husband is b- and I am o+. Should I get her retested?

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    • It would be wise to have all three of you retested. As the mother, you know if there is only one possible father and who is he. If the tests don’t line up, either the tests are wrong or you have a very rare genetic anomaly that would be great to discover early.

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  97. X

    is there any possibility that a B negative child can be fathered by O positive person if the mother is A positive ??

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    • You are correct that this is not a combination that is considered possible. As Dr. Greene points out above “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.”

      Another possible explanation — 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.

      I hope that’s helpful.
      Cheryl

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  98. Jessica

    What are the chances of a O+ male and a A- female having a child that is A-? I thought the + was dominant.

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    • Beth

      Positive is dominant however the male may carry both a positive and a negative gene. The positive trait would show as it is dominant but the negative gene could be passed onto the child resulting in a negative blood type

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    • Beth

      Ok so I just did the math it is impossible to know the exact chances as the mother could have either A-,A- or A-,O- both of which would show as A-

      If the mother was A-,A- the child would have 25% chance of being A-,O+ (shown as A+) 25% chance of being A-,O- (shown as A-) 25% chance of being A-,A+ (shown as A+) and 25% chance of being A-,O- (shown as A-) so
      to simplify that a blood test of a child of this combination would have 50% chance of being A+ and 50% chance of being A-

      If the mother was A-,O- then he child would have 25% chance of being A-,O+ (shown as A+) 25% chance of being A-,O- (shown as A-) 25% chance of being O-,O+ (shown as O+) 25% chance of being O-,O- (shown as O-) so
      To simplify this a blood test of a child of this combination would have 25% chance of being any of A+ A- O+ O-

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  99. Preeti

    My blood group A- ,my husband blood group B+ , my first son blood group AB+ . sir I am pregnant , what is any problems in second pregnancy . pls sir you are brief me. Thank

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  100. Jessica

    Hi I am A- and my husband and 2 of my children are O+. My third child is A- is this possible? I thought the + was dominant.

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  101. Marsha

    Can a mother with AB+ blood and a father with O- blood have a child with O+ blood?

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  102. Dell

    Just got a call from my daughter who donated blood today. She called to ask if I knew her blood type. I said O+. Her father and I both are O+. She said she tested A- My mother has A- and needed medications when pregnant with me because I was RH +. Perplexed. How can this be?

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    • It’s not unusual for one of the three test to be in error or remembered incorrectly. I would say re-testing the three of you would be the next step.

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  103. keriann

    im o- and my husband is a- and my son is 0+ … can that be possible?

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    • You may want to have all three blood types re-tested as this is not considered a possible outcome.

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  104. Angie

    My husband and I are both O-, does this mean our kids will be O- too?

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  105. Anthony Hammond

    Hello doctor, I am a man in blood group of A+. Can I get married to a woman in blood group of A+?

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    • What is your concern? Have you heard or read that this might be a problem? If so, what specifically?

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  106. Rachel

    Is there any need to have Ant D injection while I have group O- and my husband has A-?

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  107. Rachel smith

    Hello Doc. My blood type is a 0+ In my husband blood type is a B+ in our son ended up with 0+ does that my gene is stronger than his?u

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  108. Rachel smith

    Hello Doc. My blood type is a 0+ In my husband blood type is a B+ in our son ended up with 0+ does that my gene is stronger than his?

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  109. Rachel

    My group is O- while my husband has A-. Is it possible to have children with RH+?

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    • Only if it’s a very rare genetic mutation.

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  110. Rachel

    Hi, my father has blood group AB but I don’t know whether it was -/+ and my mother has O+ but why my group is O-?

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    • Is it possible to recheck the blood types of all three parties?

      As Dr. Greene points out above, this is not a typical outcome, but “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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  111. Angela Jamerson

    Hi, my blood type is O+ and my boyfriend is O-. Our child is also O-. What is the chance the baby is his?

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    • There is a 25% chance that a child of an O+ mother and and an O- father will have an O- child.

      If you’re concerned about the paternity of your child, DNA testing is the best course of action.

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  112. Rishabh Bhardwaj

    Hi, it’s Rishabh.

    My blood group is AB+ and my wife blood group is B-. Because of opposite Rh factor we suffered from two abortion. Now what kind of precautions we have to take because we never want to suffered from above?

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  113. Sara

    hi i am b+ and my husband is ab- my first baby blood type is b+ i had a misscarriage in my second pregnancy .. Is there any problem in our blood types.. Most importantly i want to note that i didnt take any injection after my first prevnancy .. And am planning to have a second baby now ..is there anything i need to do?

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  114. Marie

    How do I find out my sons father ? Do I have to get both bloods from two dads then compare the blood types to is?

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    • The only reliable way to determine paternity is with a DNA test. If you are considering two possible fathers, you can test one and if he is positive, you do not need to test the other. If he is negative, the other potential father might want a DNA test to absolutely rule out a third candidate.

      Blood type tests are not definitive in determining paternity.

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  115. Caroline hunter

    Hi my husband is trying to go through a DNa test with whom he has been told is his father. But the man is making things difficult.
    We know he is rhesus negative blood type.
    My husband has just found out he is also rhesus negative.
    Is this anything to go by??? Please help.

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    • Blood groups can offer general information, but not specific information. Blood groups can say in general it is possible for this person to be a parent if certain information lines up. It can not say this person is the parent. Only DNA testing can provide that level of information.

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  116. Pauline

    I am a female & have two older male siblings.
    Both parents deceased.
    I am blood group : A POSS
    Eldest brother : A RHESUS D POSS
    Middle brother : O POSS
    Are we all full siblings?

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    • In this scenario, if one parent is A+ and one parent is O+, they could have children who are either A+ or O+. In other words, it is a possible combination.

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  117. summer

    My blood group is B positive and my wife blood group is O positive; Is it possible for us to give birth. On what percentage of change do we stand giving birth and our children’s blood group

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    • If one parent has B+ type blood and the other has O+ blood their children could have B or O, + or – blood types. The blood type can not be used to determine percentage chance of giving birth.

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  118. Nana Addo

    I highly impressed education on blood type

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  119. khushboo

    hello dr.
    my blood group is O positive and my husband having O negative blood group……can i conceive baby or not????

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    • Your blood group will not impact your ability to conceive. There are, however, many other factors that come into play when determining you ability to conceive.

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  120. gautam

    If a female has a blood group of “o+” and her husband of “a+”
    what is possibility of blood group of “b+” of twins born as boy and girI. Please answer give me very fast.

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    • If one parent is O+ and another is A+, their children will have either A or O type blood. There is a 6.25% chance each child could be Rh-. Before jumping to any conclusions, it’s very wise to have everyone’s blood type re-tested.

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      • gautam

        I am submitting a society problem which has now become anti social habits of disputes ultimately felt into legal case before court which is as below. A male married on 30 January 2001 and suffered with diabetes in 2005 year.as per family background, his father, grand father, cousin brother also suffered with diabetes and special kind of perkinsons disease also such man using medicine of ayurvedic , allopathic of diabetes with insulin injections as 2 when needed. His blood group “a+”.his wife moving blood group of ” o + “. During pregnancy, she used ayurvedic medicines for ensuring birth of boy as desired by her husband. After seven and half months of pregnancy, twins (one girl and a boy) born having blood group of ” b+”.suddenly, husband created problem with allegations of paternity of twins on the ground of “b+”blood group with support of genetic books.one of book of genetic of your also by which husband claimed and challenged the paternity of twins to other.he also filed a legal case before court of law.
        I request to kindly guide about the blood group of ” b + ” of twins and reason of it.is any effect due to suffering of diabetes insuline injection used by male and ayurvedic medicines taken during pregnancy by female also on blood group of twins as “b+”.I also request of your support due to genetic researcher and expert of your goodselve in this matter that which arguments from the side of female about blood group of twins as ” b + ” may be made before the court to save life of twins and also to get rid of bad allegations of paternity in the matter before court of law so that legal case mill be decided in favour of female on the ground of paternity in good spirits and faith of both may be made again by saying relations of husband and wife with their twins. Male always uses energy tablets since marriage. It is also submitted following of your message received- “if one parents is “o+” and another is “a+, there children will have either ‘a’or ‘o’ type blood. There is a 6.25% chance each child could be Rh-
        request to simplify public language the meaning of a 6.25% chance each child could be Rh- so that it any supportive meaning received in favour of female which may be submitted before court of law.

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        • In this case, DNA should be used to determine if this man is the father or not. The tests are fairly easily accessible and reasonably priced in the US, Canada, and Europe. I don’t know about the rest of the world. Blood type alone can’t determine paternity for legal purposes.

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          • gautam

            Resp. Sir
            thank you very much for your reply dated 24th August 2015 .sir we do not agree to DNA test at this stage due to children are having age of 8 years and their elder sister is 14 years old who knows the merits and demerits or prons and cons of DNA. Hon’ble high court of Rajasthan ,Jaipur has given an verdict that children will have bear the results of DNA so DNA not allowed such test .I have asked about blood group of ” a + ” of male ,”o+”of female and twins are “b+”.kindly give me any helpful reply which may be quoted before court of law so answer must be supported legally and can be argued before court of law up to its satisfaction resultant.

            Added:
          • I am sorry for your situation, however, with regards to blood types and paternity, I will quote from Dr. Greene’s article above:

            “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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  121. Newton

    what are the chances of having healthier babies when blood groups are B+ and B?

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  122. Elvis

    Dr, I’m sort of convinced my fiancé is RH O- while I’m B+. What are the chances of us having healthy babies?

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  123. Christina

    If I am o- and my sons father is o- is it possible he’s not my sons father if he is also o-??? I have researched everywhere and I have not found and an answer! Please help!!!

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    • Jane

      If both parents are O the child has to be O.

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  124. Sakib

    Doctor…..my wife’s and my blood group is o positive….and we are bloood related person.is there any problem to have a baby??

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  125. sushil

    My bloodgroup is B positive, my wife bloodgroup is B positive. What is my child”s blood possibilities? Please, urgent.

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    • Two B+ parents can have children who are blood group B or O and be either + or -.

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  126. SP Asapu

    Hi, My blood group is A(+ve) and My Wife blood group is O(-ve). What will be the possible and impossible blood groups for our Children.

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    • There is a 75% chance that your child will have type A blood and 25% chance of type O. There is a 75% chance your child will be RH+ and 25% chance of RH-. Each child has the same odds.

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  127. Lisa trenda

    Hi I have B negative blood. One of my children have B negative and my other child has o positive. They have the same father what would be his blood type.

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  128. Ebenezer Ampaabeng

    Doctor, can a Mum with genotype AA and a Dad with genotype AS give birth to a child with genotype AC? Why?

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  129. Via

    Hello. My blood type is A+ and my husband is B+, what are our chances of conceiving? Are we compatible?

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  130. Mamta.n Shetty

    My blood grup o+ and my husband blood grup also o+
    so now i am 7munths pragnant so my baby had any problem

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  131. Glenda Sainz

    My blood type is 0-. My mother was 0-. what are the possiblilties of my fathers blood type?

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  132. rupesh kumar

    my blood group is o negative
    so what is blood group of my
    father and mother…

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    • YC

      Your father can either be A or B or O but never AB

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  133. Debbie Jaime

    Hello Dr. I need your help my Mother was blood type A+ father was an O+, two of my brothers are A+ and 2 sisters are A+ like mom. I am O+ but 1 brother is AB+ does this mean he is not my father’s son?

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    • YC

      Yes looks like it

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  134. tps

    Can a a positive female and b negative male get married. Will there be any problems during pregnancy

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    • tps

      Can a female with A+ blood group and male with B- get married. Will threr be any problem during pregency

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  135. jenny

    if mother is b- and father a- can child be o-

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  136. lu

    my mother is ab + and my father o + and I am o+ it is possible

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    • YC

      Not possible

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  137. Jessica Lee

    Hello, DrGreene. According to my mother blood type is AB(whether is positive or negative, I don’t know),My father blood type I also don’t know. (I think is o positive!). They don’t want to go for blood test.Mine and my brother is A positive.I am the eldest.I was borned in 1972 year. My btother is 2 years younger than me,he is ok. But i just want to know what is happened to me if my parents blood type is like this??

    I am so confuse about myself and very appreciate if you can answer my question. I am from Malaysia.

    Thank you so much.

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  138. Katie

    I am Rhesis A – my baby has been born o- can the father be b+? Need help

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  139. Gimo

    My wife has o negative our son turned out to be o negative,am o positive,,is it genuine?

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  140. Maggie

    Hi,

    My mother is 0-. Is it possible for her parents to be A+ and B+?

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  141. Aniket

    My blood group is O RH positive & my Fiancee has A negative…what is the possibilities of having baby…with this blood group..can we have only one baby…or more?

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  142. Lucy

    Can a mum who is a, dad is o make b type?

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    • From what we know of genetics at this time, the answer is no. However, tests are not always accurate. It’s not unheard of for one of the three tests to be incorrect.

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  143. Aref

    if both parents are blood group O plus , and my child is A plus, it’s possible ?

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

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      • YC

        NO.

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      • Beth

        Ummmm… No it’s not.

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        • Oh, my. I must have mis-read the original question. I am chagrined. And Beth, you are correct.

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  144. Jo

    Mother is A+ father is B- and I am O+. What are the chances that my father is truly my father? I know my mother had other partners in the same time frame, I can’t get DNA, as my father is deceased. Thank you.

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    • Odds are an interesting thing in blood types. I can tell you that the odds of a mother with A+ and a father with B- having a child with type O blood are 6.25% and the odds the child will be Rh+ are 75%. But for every child the biggest question is “can this parental combination produce “X” blood type child?” In this situation the answer is, yes.

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      • Carly

        My blood type is A +, my baby’s father is B+. Our son is 0+. Since I have never slept with anyone else since I married his dad, I can tell you it is possible.

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  145. Janelle

    I’m O- for sure. My husband does not know his type. We have three children together. One is A+ and two are B+. Is it safe to say my husband is most likely AB+? I know he’s the father, no question of paternity, just scientific curiosity. Thanks.

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    • You are correct, he would be AB+ because that is the only blood type that could be the father of children with either A+ or B+ if the mother is O-.

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  146. meena

    hi, my blood group is B – and my husband is AB+ what precaution we have to take before pregnancy????

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  147. Shay

    Hello I’m O+ and my baby is B+ and her father is B+ is that a good way to be certain that he’s her Father?

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  148. vicky shaw

    sir,
    I am ab- negative and my wife is o+ positive blood group ,so our born baby have any problem?

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  149. Lynnrose

    My type O+ and my husband AB+ and I have sex only with my husband and my son is O+ and my daughter O+ so are you saying its impossible…

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    • Perhaps you and your husband should have your blood type tested again. It’s amazing how many people think they know their blood type and find out it’s different than what the believed it to be.

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  150. theresa

    hi, am A+ and slept with two men… one is O+ and the other is A+.
    My child came out to be O+, would like to know who have the highest possibility as her father and how many percent accuracy would that be?
    I understand our parents (child’s grandparents) blood type would also affect my child’s blood type – if so how could I determine without going for paternity test?

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    • If the mother is A+, here are the possible outcomes:

      – If the father is O+, the baby has a 75% chance of being type A and a 25% chance of being type O and a 93.75% chance of being Rh+ and 6.25% chance of being Rh-

      – If the father is A+, the baby has a 93.75% chance of being type A and a 6.25% chance of being type O and a 93.75% chance of being Rh+ and 6.25% chance of being Rh-

      In other words, it is not possible to know the father of the baby without a paternity test.

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  151. michelle

    Halo. If I, the mother has a bloodtipe o- and slept with 2 diffrent men the ones bloodtipe is o+ and the other is a+, which blood tipe would it possibly be, so that I would know which of the 2 is the father of my baby? So confused at this stage.

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    • We know you are O- (and I assume you are really sure of this):

        — If Dad is O+ the baby will be type O and can only be type O. 75% chance of being + and 25% chance of being -.

        — If Dad is A+ the baby has a 75% chance of being type A and a 25% chance of being type O and a 75% chance of being + and 25% chance of being -.

      What this means:

        — If the baby is type O, it could be either father.
        — If the baby is type A, the type A man is the father.
        — The Rh (+ / -) does not help rule out either man.

      If the baby has type O blood, DNA paternity testing can help you determine which man is the father.

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  152. Victoria

    My son is blood type o positive and my boyfriend is o negative. What are the chances that he is my son’s father?

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    • It is possible if your blood type is A+, B+, or O+

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  153. Samantha

    My mom is A positive and my dad is O positive. My sister is O positive too, however I am AB positive. Looking at multiple blood type chart it consistently indicates that an AB positive child is impossible. Is that true or is it possible under certain circumstances?

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  154. Anonymous

    Dear Doctor, my father’s blood type is AB and mine is O, is it possible that he is my father? I wonder if you can send me an e-mail to this answer?

    Regards!

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  155. Cindy

    The father is AB+ and the mother is O+ and they have a son who is O+. These parents are both white. The mother had no other sex partners. Are you saying it is impossible for them to have an 0+ child?

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    • Arenae

      I am O+. My dad is type AB and my mom is O. Research “Bombay” blood type or hh blood type. It will give you more explanation as to why this is.

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  156. Archie

    My mom is B+ ve and dad is AB. I’m O positive.. Is it possible?

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    • I’m assuming you’ve looked at the chart on this page? If so, your real question may be, “what do I do now?” There are several options. I recommend that you talk to your mom first and tell her your fears. If she is firm that your mom and your dad are your biological mother and father, then it’s pretty easy to get everyone retested to make sure the blood types are what you think they are.

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  157. David Nandwa

    My blood group is o positive and my wife is b negative. What precautions can we undertake to our unborn baby. She is 6 months pregnancy.

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    • Velvet

      My ex has your blood type, I have your wife’s.. Hopefully your dr. Has already given her a rogam shot so the babies blood is not fighting her blood.. I hope her pregnancy is going well..congratulations

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  158. Emmanuel Yeboah Dunga

    if both parents are blood group O, then, under normal circumstances, all the children should have blood group O and no other group. But you can do the testing again if there is any doubt

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  159. Lori T.

    Hi my mom said she is AB- and my dad is B+. I’m O-. I know my mom has the RH negative factor, which I have as well. Is it possible my dad is my dad?

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  160. Susan Knight

    My parents are both A positve…I am B negative…is this possible?

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    • There is a small chance that two A+ parents could have a child who was Rh-, but two parents with type A blood can’t have a child with blood type B.

      Before you jump to conclusions, it’s wise to have all three of you tested again to confirm your blood types. It’s not unusual for people to think they are one type when they are another.

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  161. Reynaldo

    me and my wife are type O but my eldest son blood type is type AB. Is it Possible?

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    • Tina

      No, sorry to have to inform you, but its not possible. Maybe you all should be retested.

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  162. Namrata

    My Blood Group Is A+ and My Husband blood group is O- Please let us know which blood group or children will have? Also please let us know what are the precaution we have to take during the pregnancy? And is there any problem in making baby if blood group is A+ and O-

    Thanks & Regards,

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    • mary

      I am too trying to find this out.I am a pos,and ex is o neg,my daughter is o neg.

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      • There is a 25% chance that each child of an A+ parent and an O- parent will be O-. If you are concerned, DNA testing can give you specific information.

        Best,
        @MsGreene

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  163. Martin Luther

    My Blood Group Is B+ and My Wife is B- Please let us know which blood group or children will have? Also please let us know what are the precaution we have to take during the pregnancy?

    Thanks & Regards,
    Martin Luther

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  164. vinit

    My blood group is B positive & my wife has B negative…what is the possibilities of having baby…with blood group..can we have only one baby…or more???? Reply fast plzzz. It’s urgent! ***plzzz

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    • sakshi sagar gaikwad

      my blood group b negative & my husband blood group b positive whats complication pregancy please reply me fast

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  165. Nikhil

    My blood group is B positive and my wife blood group is O positive; Is it possible that my baby have blood group O negative.

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  166. Michelle

    Hi Dr, both my parents are O and I am A+. My mom had lots of blood transfusions before I was born. Is this possible?

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    • Vivian

      Hi Dr, I am O – and am looking to become a single parent with a sperm donor. Can you tell me what blood type to avoid please? Or if there are any complications with my blood type and any other blood type?

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