(June 8, 2011 at 9:10 pm)FaithNoMore Wrote: As far as I know, behavior does not change brain structure. This doesn't mean you're wrong, you just need to show something to back that up.
Certain activities do affect the brain, such as playing Tetris, for example. See this article.
As a parallel argument, it would be incorrect to say that all the Tetris addicts do not have a choice in playing Tetris just because their brains are like that. Rather, what happened is that the structure of their brains changed as a result of playing Tetris. In the same way, it's' also possible that the brains and/or the genes of homosexuals were changed or altered as a result of homosexual activity (although I didn't see any evidence for that).