Do your own research. I have. I don’t have to rely on what a politician, clergy, or my straight friends ‘believe’ to be the case. I asked dozens and dozens of gays years ago, and over several years, how and why they ‘chose’ to be gay. I got the same answer every time, and never did I get the impression I was being lied to.
Believe what you like. I do.
What a gay “thinks”about his sexuality is conditioned by his experience. As often as not, he is attracted to a particurlar person and the sex was only part of the attraction. It is a way to get close to that person if he/she reciprocates. A man might for instance feel attracted to both a brother and a sister, because they have the same qualities.
I have done the research. There isn’t a shred of proof, replicated or credible evidence homosexuality is genetic. There is a mountain of evidence that is has a environmental cause.