I'm a bit confused about my baby's blood group. My husband has a B blood group and mine is A, but somehow our baby's blood group is O. Could you help me understand why this might be? Is it something I should be worried about?
The inheritance of blood type is based on mendelian genetics. For ABO blood typing, if you are A and your husband is B, there is 25%chance of your baby being O. This might be because your genotype would be AO and your husband's might be BO. So based on probability, 25%probability each of baby being A, B, AB or O.
Similarly for Rh factor inheritance, assuming you both were Rr, you have 25% chance for RH negative baby.
To conclude.. its possible for a A+ and B+ couple to have O- baby. You are proud parents of a universal donor