There are a lot of articles on this right now, so I thought I would put this here. Others can contribute better ones if they so wish. I just thought PBS did a decent job in explaining the situation. Basically, a study in genetics has revealed a "gay gene" doesn't exist, but that same sex behavior is influenced by many small genetic factors (as well as environmental and social factors). However, the genetic influence is only accounting for 8 to 25 percent of same sex behavior. The limitations in the study were that they only studied people who had same sex sex, instead of those who also identified with same sex behavior but had not been sexually active with someone of the same sex. They also left out people who were trans or intersex. The other limitation was that they had access to mostly only people's genetic data that were of European descent, meaning they have not been able yet to study other parts of the world and how this is similar or different. However, it is a massive study, so it seems to be well done.