Interesting Biological Question
I'm sure this has been brought up before somewhere on the web, but I thought of it listening to several different conversations over the past 5 hours (by the way, I've had 4 20-oz coffees in the last 24 hours, which is why I'm still blogging 8 times in 8 hours)
Conversation 1 had something to do with genes all having to have some purpose - I think it was an extension of Dawkins' selfish gene theory, but I don't remember them actually saying his name.
Conversation 2 was two of the gay guys down the hall debating with a couple of straight guys about the gay gene thing. I tend to think that genetics does at least somewhat influence sexual orientation (but not that whole "transgender" thing - that's psychological, IMAO), but where my brain led my train of thought next rather surprised me.
1) All genes must serve a purpose
2) Sexual orientation is caused by genes
3) One who is true to their sexual orientation does not get their genes passed on.
Why would this one gene (or numerous genes) hold epistatic properties over the ENTIRE human genome? That doesn't make sense. Therefore, there are only four possible answers.
1. There is no actual gay gene, but perhaps hormone level and the like influence sexual orientation.
2. The entire process is psychological and there is no gay gene.
3. Something about the rest of the genes requires that at least several of them are not passed down.
4. Dawkins' selfish gene theory is completely flawed. (Debunking Selfish Gene Theory gets no matching results on Google) Since Dawkins' selfish gene theory owes itself in part to Darwin's theory, we've got another problem on our hands there.
To me, #1 and #3 seem like the most likely answers. EvoWiki somewhat goes into detail on #1 here. Makes enough sense. #3 should creep you out a bit though. It seems as though if we finally discovered a gay gene, we would have to admit it's there for a reason - because the rest of the genes have something that requires that they don't be passed down. What politician would EVER spread that message, or legitimate science journal? "You're naturally this way because the rest of your genes suck."
Maybe the gay community shouldn't be looking for a gay gene to explain this after all. Along with the Eugenics movement, they should really stay away from the gene-hypothesis angle, because by the looks of it, they're only asking for trouble.