Probably a stereotype but Lesbians never seem to like men. They even seem to “hate” men. I have known a couple of lesbian couples and they always seem to avoid me. My wife, no. And I am always friendly. Rose O’Donnell doesn't like men. She even had a bad relationship with her father.
Surprised that this has never been considered.
Obviously this would be difficult to study under controlled conditions, although there is (was) a lot of anecdotal evidence. It also explains why identical twins raised under more or less identical circumstances in the same home choose different sexual orientations, although there could be lots of other reasons for that.
The genetic theory has only gained currency because homosexuals realized that as long as their lifestyle was a more or less ordinary perversion arising entirely by choice and habit they could not lay claim to the bonanza of special civil rights protections of a grievance society. Unfortunately, there is no evidence that for females it's true, and no compelling evidence for males that the genetic correlation is determinative in any strong sense.
It's a mild form of mental illness that we don't as yet have very effective broad-spectrum treatments for. Like most people suffering from mental illness, most homsexuals don't believe there's anything wrong with their minds. Sadly, in the current political climate, even if a treatment becomes available, they won't be allowed to use it.