What Blood Type Does the Baby Have?

Question

If the parents have blood types AB and B, how can you determine the baby’s blood type?

Answer

The ABO blood group system is controlled by three antigens, each governed by the A, B, and O gene types. During blood type inheritance, each parent contributes half of their genes, combining to form six possible genetic combinations: AA, BB, OO, AB, AO, and BO, corresponding to four phenotypes: A, B, O, and AB. For parents with AB and B blood types, the father’s genetic type could be AO or AA, and the mother’s could be BO or BB. If the father is AO and the mother is BO, the child’s possible blood types are A, B, O, or AB. If the mother is BB, the child’s blood type will be fixed as AB or B.