> From a high level view, the idea that something that is so critical to species survival, like a sex drive, isn't largely genetic determined seems rather unlikely.

Actually I found that surprising to hear. We have so many social processes that in many cases discourage and reduce sexual behavior.

Marriage works against the survival of the fittest you might get from sowing wild oats, but it's almost universal.

Homosexuality, indeed, is a discouragement to species survival (if I understand your meaning correctly). Yet you're claiming it is unlikely that it doesn't originate in genetics?

I don't know, I mean, I basically agree with your final statement - that we don't actually have a discrete variable here even if we largely see discrete behavior (since we tend to prefer long lasting relationships, so if you're F45-55M then you'll probably focus disproportionately on finding an M partner).

And what it means to be a guy or a girl is definitely not genetic. Most of our interaction with sexual beings is "pants on". And those pants, and the nature of our interactions, is hugely cultural determined.

And I think most people have the experience of being attracted to a person without engaging in any sex-seeking behavior with them. And many people seem to have experience of the reverse.

Given the cultural and experiential components of sexual attraction, I really don't think genetics need to be worth that much. Maybe there's some contribution, but it doesn't seem to have much scope, nor does it need it.