Question

As a genetic counselor, you would explain to the parents that

A) the eggs must have been accidentally switched, since a type A parent and a type B parent can
have any type children except O.
B) each parent could have contributed one recessive allele, resulting in type O blood.
C) the eggs must have been accidentally switched, since the baby's blood type has to match one
of his parents.
D) it is possible for the baby to have type O blood, since type O is inherited through a dominant
allele.

Answer 1

Yes, a child with blood type O can be the legitimate child of parents with blood types A and B if each parent contributes a recessive i allele.

Step-by-step explanation:

The question asks about the inheritance of blood types and specifically whether a child with blood type O could be the legitimate offspring of parents with blood types A and B. In the ABO blood system, the genotype of a person with type O blood is ii, which is recessive. If one parent has blood type A (genotype IAi or IAA) and the other has blood type B (genotype IBi or IBIB), they can indeed have a child with blood type O. This is because each parent can contribute the recessive i allele. Therefore, the correct answer to this question would be that each parent could have contributed one recessive allele, resulting in type O blood. ABO blood groups are an example of codominance and multiple alleles.