I've been wondering for quite some time if genes are responsible for our sexual preferences. Is this determined by our chromosomes or is it our mindset that makes us like our gender/both genders/opposite gender or even feel like we belong to a different gender. I'll be really happy if there's a logical scientific explanation cuz I'm sick and tired of reading hateful comments bashing gays/bisexuals for being crazy.
As far as I know (please correct me if I'm wrong) it is not comepletely understood what exactly determines sexuality. It is thought that it's a mixture of both genetic predisposition and environmental facotors that come to play. Until now, no gene has been found that is responsible for sexual orientation. In any case, sexual orientation is not a choice.
What Skaros said. There's a great book by Simon Levay called Gay Straight and the Reason Why. He examines studies from rats, for example, which look at fetal development and what happens when the fetus is given too much estrogen or testosterone during certain parts of development and at different stages. I'm not a scientist, so you'd best give the book a read yourself as any synopsis I provide just won't do it justice. If you're interested in what science has to say about the probable reasons for homosexuality, I'd highly recommend checking it out.
I think the more interesting question is whether or not we want to know the determinants of sexuality. On the one hand, finding a biological foundation may improve LGBT+ rights because people are more likely to unanimously agree that sexuality is innate and not something that can be changed. Furthermore, it would be more difficult to discriminate based on biology. However, not everyone respects scientific evidence so perhaps it wouldn't change anything at all, especially if considering religion. On the flip side, the moment those determinants are found, someone, somewhere, is going to start working on a solution to "fix the problem". The line between medical conditions and general human disposition is getting more blurred by the day. What if non-heterosexual individuals are treated as patients with some sort of illness, disease or disability? Are people going to mandate that such individuals should be treated in order to conform to the majority? Are people going to start taking measures to ensure they can avoid any causative agents of non-heterosexuality? Ultimately, I think it would be better if the LGBT+ rights movement continued to work on changing society through compassion rather than seeking a biological route as a means of strengthening calls of discrimination. Personally, I cannot help but believe that if biological determinants were to be found, people would either dismiss the findings or do everything in their power to minimise the number of non-heterosexual people in the community. It's also important to remember the discussion is at different points in different parts of the world: while we are making good progress in the western world, there are many countries where LGBT+ rights are nowhere near as developed. As a medical student this question has interested me a lot, but now that I've thought about it I'm fairly comfortable thinking that I'd rather not know the determinants. However, I'm only one person and I respect that people have different views to myself, and I obviously don't get to make the call.
And brain changes always have the potential to override that. There are fascinating findings regarding brain changes and sexuality changes through case studies.