Sexual orientation cannot be explained by genetics or environment only. However, a team of researchers based at UCLA examined the role of epigenetic on sexual orientation. Using 37 sets of male twins, researchers have identified five epi-marks in the genome that could be associated with sexual orientation. The team claimed that sexual orientation could be assigned with a 70% success rate, but they were highly criticized for their poor use of statistics and the lack of a published article (the findings were presented at a conference). It seems like more work needs to be done to examine the possibility that epigenome and sexual orientation are linked.