I think we've discussed this before.
Given the current evidence about this particular trait and complex traits in general, here is my view as a biologist.
No, there is no "gay gene." There are a collection of genes which in aggregate tip you one way or another.
There is also an effect of in utero environment, which is an effect of hormones, diet, excercise, and genetics of the mother. These also tip you further one way or another.
There are likely environmental effects as well (dioxins, diet, etc) which FURTHER tip you one way or another.
Finally there's the psycho-social aspect of your environment. There's increasing evidence that strong social pressures can actually *change gene expression profiles and brain patterns.* And this tips you yet again one way or another.
Take this in aggregate, and integrate it, and you get your sexuality.
Sexuality, like most things, is a poly-causal trait. Which is why the genes have been able ot stay in teh gene pool without being wiped out (a discussion I could go into, but this isn't likely the venue for it).
People on both sides of the issue want ot make it simple. Biology isn't simple. Even simple biology isn't as simple as we often think it is. Everyone needs to learn to accept that.