That's easy. It covers single-parent kids.
What I want to know is what the hell is an "atypical hereditary cellular or blood trait"????
AIDS??? HIV??? or just blood type??? Maybe I've got some moles, or warts, or ........
WTF?????????????????????????????????????????????????????????????????????????????????????????????????????????????????????
Disease or inherited diseases.
They meant AIDS, but did not want to limit themselves, it would also include diabetics and other groups.