Actually more than one gene controls blood type. If the gene that makes the 'stem' for the antibodies that cover red blood cells are not created because of the recessive phenotype of the gene that codes that, no antigens are made for the blood, making it seem as though the blood is type O, which also has no antigens in the blood. So it could just be a different recessive allele other than the one that codes for blood type. You might just be okay.

well there are both dominant and recessive alleles. Estimating that both your parents are A and O their recessive allel is b. this leaves the options Ab, Ob, AO, and bb so bb is probly what you have guessing that their recessive is b

"My daughter of a past affair I have hidden from my husband, finally turned 18 and went off to donate blood. Which she of course found out was type B. Sadly, my husband is biology professor knows it's genetically impossible to have a child that is type B blood if he's type O and I'm type A. FML"

wow, fml actually taught me something! OP, i hope everything works out !

I'm going for illegitimate child. I am so sorry.

Dude that really sucks, that basically means you're adopted. I'm sorry man. Even if one of your grandparents had B, that doesnt affect blood type. Blood type is strictly from your parents. :(

for your information it IS possible for you to have a totally different blood type. There was an article about how a teen commited suicide because his blood type was different from his parents. But in fact his parents were his actually parents. Mutation is not a bad thing, so don't be so paranoid about having a small mutation in the blood type. at least you don't have Down symdrome.

It is possible actually my Mom and Dad are different blood types and most of the kids in the family are 0 positive, my mom and Dad are A's and B's

well im a genetics student and i can tell you that its possible that theres nothing weird going on and youve just got a mutation in the gene, but thats nothing to worry about since that mutation is shared by over 10% of the world... but in all fairness thats unlikely and your probably not your fathers child...but imo who raised you is more important than who had sex with your mother...

That sucks!! If it was Bombay Phenotype case than OP would have O blood group. Since he is not that, Bombay Phenotype don't apply here. Go for DNA Test!!!