You can look at t from the Nature vs nurture debate in my opinion both are influencing factors but to what degree is difficult to tell.
In some cultures and some people take the same attitude that a man having sex (ie penetrating another man) is just sex and not being homo sexual where the man that is penetrated is homosexual.
Interesting question came up after finding out gay men donate sperm much more than heterosexual men. Well my nephew who we knew was going to be gay from a young age was a result of donor sperm, he has a twin brother who we never though would be gay but he is now. He is quite different to his brother in many ways so not sure if his brother had any influence on him being gay.
LOL I consider myself to be a bit homophobic.
I have an issue with IVF, don't like the idea of gay men paying for a surrogate to have a child. Come countries gay men can't adopt a child, like that idea. As for lesbians, apparently they can access donor sperm and not just via a fertility clinic LOL
