What's the jib with people disliking people whom are bi/lesbian/gay? I see nothing wrong with those type of people, they're just like us but with a unique sexual orientation.
I have a step brother who is gay and evidently my parents knew he was gay before he, himself knew. I'm sure there is enough evidence to support the theory of something hormonal/chemical that switched the way of thinking. You know, it has to be. If you think about it being gay was something frowned upon, but now it is more open. The number of gay people seem to increase, maybe through years of this gene or chemical being mutated in some way. Although you could also say that because being gay was taboo, there were a lot of gays, but you just never heard of them.