(a): If fertilization takes place between gametes of Rh− female and Rh+ male then the resulting foetus' blood is Rh+. The Rh+ blood of the foetus stimulates the formation of anti Rh factors in the mother's blood. In second pregnancy (with Rh+ foetus), the anti Rh factors of the mother's blood destroy the foetal red blood corpuscles. This is called erythroblastosis foetalis. New born may survive but it is often anaemic. The Rh− child does not suffer.