As far as the male homosexuals go, no, I would say that the dick needs to be hard in order to impregnate. If the man isn't attracted to the woman, then he will definitely not get her pregnant. But, don't worry, there are always plenty of horny heterosexual men around that will execute the deed. And, homosexual men can help their fellow humans survive by helping them.
Not every male homosexuel is 100% oriented towards men only. Most in fact, are not. If it means the difference between being an accepted member of society or being a 'depraved' outcast, quite a few will be perfectly capable of 'lying back and thinking of England' so to speak.
Something like this happened in Game of Thrones where the new wife of the king
even offers to get his lover involved just to get him hard enough to impregnate her.