Agreed. There clearly isn't a gay gene -- if there were, evolution would have weeded it out -- but to call homosexuality a choice is to miss the point as well. It's certainly a pervision, and I believe it's wrong. But that doesn't mean someone woke up one day and decided to be attracted to men. Something happened in their lives to cause them to be confused about their sexual identity. We won't make any headway by telling gays simply to choose differently; we have to adjust the cultural circumstances that make such confusion commonplace.
A well reasoned response, and I agree that we need to put the political correctness aside and be open minded so we can find the cause.
Are you sure about that?
First of all, I'm confident there is no such gene. But, if there were, it wouldn't necessarily be eliminated by "evolution" (or survival of the fittest).
Think recessive vs. dominant, as with blue eyes vs. brown eyes. I'm no expert, but I know there are genetically-transmitted abnormalities which are so recessive that only a rare genetic combination will cause the abnormality to appear, when both seemingly-normal parents (as well as the siblings, and some or all of the grandparents, etc.) are carriers.
If there were a gay gene, how would it be passed on if its bearer doesn't want to have sex with members of the opposite sex?
Oh, the gene very well could be passed on and survive if it provided a greater reproductive advantage in the homosexual males' siblings than it cost in missed direct reproduction. For example, if there was a gene which increased the propensity toward homosexuality in men, but, in women, greatly increased fertility or made for healthier babies, the advantage the gene would have when expressed in women would be selected for by natural selection and preserved, notwithstanding the reproductively deleterious effect it has when expressed in men. Even if it man some men gay, it would be preserved if the same gene increased the fertility of those men's sisters. (N.B., I am not saying this is what is actually happening, just presenting a plausible reason why it is not, per se, impossible under natural selection.)
I'm inclined to think there are combinations of genetics and chemical states in the womb that give rise to a variety of ways that persons "become" - of which homosexual is one. There's no particular reason for Darwinian evolution to quickly weed out combinations that happen 2% of the time when virtually the same DNA also produce 98% people who turn out hetero.
I don't think we should be in a terrible hurry to figure these things out. Look what happened with eugenics - disaster. I doubt there is anything preventive that should be done, culturally or any other way. Let people be how they are.
However, don't change the institution of marriage as an accomodation to homosexuality!