sciencehabit writes: From a strictly Darwinian viewpoint, homosexuality shouldn't still be around. It isn't the best way to pass along one's genes, and to complicate the picture further, no "gay genes" have even been identified. According to a newly released hypothesis, the explanation may not lie in DNA itself. Instead, as an embryo develops, sex-related genes are turned on and off in response to fluctuating levels of hormones in the womb, produced by both mother and child. This tug of war benefits the unborn child, keeping male or female development on a steady course even amid spikes in hormones. But if these so-called epigenetic changes persist once the child is born and has children of its own, some of those offspring may be homosexual, the study proposes.