Sorry, I wasn't very clear. What I mean is, if a father with the gene had one gay child, and then fell out a tree and died, the gay child wouldn't reproduce and the gene would die. So that gene would be more succesful if all the other genes insured pre-mature deaths didn't happen, perhaps suggesting it originated from well-off tribes.
Gayness is a cultural phenomenon, and quite a young one. It's impact on the spread of genes probably has had zero effect on the gene pool. Until recently, homosexual sex didn't preclude one from having a family. Nobody identified as "gay" until very recently in evolutionary terms, even though males have been having sex with males since long before the dawn of man. For a measurable effect on inheritance, we'll have to wait a lot longer than a handful of generations.