It would especially limit the “I had an abortion and am proud of it crowd”. As to whether it would be legal, this is really a fuzzy area of employment law. The Pro-abort types would argue that they have a religious right to abort and you're interferring with their religious beliefs
There’s one theory where there could be a genetic basis for homosexuality. Assuming there’s multiple alleles involved, it’s possible that carriers of some of the alleles get a reproductive advantage that compensates the disadvantage of a homosexual pheontype. Suppose that female carriers of the male homosexuality genes wanted to have sex with males more than the average - and hence had more than the average number of children. It is possible that that could compensate they’re male children having no offspring.
The interesting thing about this is that in the modern world because of birth control the amount of sex has been strongly decoupled from fertility rates. This means that the homosexual genes should leave the population as the base comment argues...