"My mother made me a homosexual" is something gay men say so often of overbearing matriarchs it has become a cliché. There's research that shows male children with three or more older male siblings show a vastly increased incidence of homosexuality. My first close gay friend said he was only aware of his homosexuality after an approach by an older male in a public lavatory. These cannot be exclusively biological. More likely is a predisposition awakened by environmental factors.
Whoa, I come back to the forum to find this?
I know a lot of gay men, and none say being gay had anything to do with their mothers. That is another sexist cliche' -- a child is autistic? The mother. Child is gay? The mother. This is like some 1960s type thinking.
Can you link me to the research that says male children with older brothers increases the tendency to be gay? (And what does that have to do with "overbearing mothers"?) Or could it be that, statistically, the more male children in a family, the more likely one might be, you know, gay?
Do you believe your gay friend became gay because he was approached by an older man in a restroom? Or maybe in that moment, he realized that his feelings were not an outlier? (I am against older men approaching a child of any sex in a restroom, by the way, though I don't know how old your friend was at the time.)
And perhaps it is genes, or a combination of genes and environmental factors, or whatever. Why does it matter? I believe gay men and lesbians are telling the truth when they say they have always been attracted to the same sex. They don't need to find a "gay gene" to know this is true. Gay people have been around since the beginning of human history. It just IS. But the way we deal with it as a culture is different -- some cultures demonize, others "tolerate," and others accept them.
No disrespect to you, as you seem to be an intelligent, well-read fellow, but when it comes to this topic, I think you have failed here, and might be more informed by your personal beliefs, which is fine, but you should state those out-right.