"It's probably genetics and environment."
That is the laziest, most half-baked retort I've ever read here.
Since you are so lazy, I googled "is there a gay gene" for you and the answer is NO. Here's the link, for your spare time.
http://www.narth.com/docs/istheregene.html
The radicals pushing the homosexual agenda have been talking about this gay gene for a long time. Here's another great summary on the science surrounding the issue: Born or Bred? Science Does Not Support the Claim That Homosexuality is Genetic.
He will put it in the same category as the AFA article. (he discounted that one b/c he hates the "wal-mart hating AFA"). Its a bit of deflection to refocus the conversation.