If you follow Darwinism, which puts great stock in minute differences, such a strong inclination against reproductive sex would be self-eliminating. After all, a stripeless tiger is still a deadly predator.
But if the man is correct, it isn't really a matter of genetics anyway. Could be, the human brain is programmable in this regard, and certain early experiences tend to bring about bad results.
There are people that get sexually fixated on a car. Programming is definitely possible. I certainly get the feeling that a lot of lesbians are just ugly women and/or liberals who are trying to prove how out of the mainstream they are.
As for homosexual men, I just don't get that. I can barely stand a proctology exam.
Yes, but if it’s genetic...which I doubt...throughout history women have had little or no say in matters of reproduction. They were given in marriage to whomever their parents chose. There was no birth control. Not to mention all the non-marital situations.
Marry she usually did, and procreate she did, even the humpbacked woman that Thackeray postulated. So about half of any genetic source of homosexuality was not self-eliminating.