Question

If a Rh positive homozygous man marries a
women heterozygous for Rh, what is the
percentage of the children affected by
erythroblastosis foetalis?
1) zero 2) 25%
3) 50% 4) 75%

Answer 1

Answer:

The answer will be (a) 0%.

Explanation:

As we know, erythroblastosis foetalis occurs in a child with an Rh positive father but Rh negative mother. The disease is caused due to production of antibodies in the mother's body against the Rh antigen that the child receives from its father.

If the mother is heterozygous for the Rh gene, her body is used to the antigen, hence antibodies will not be produced against it.