A team of international researchers has completed a study that suggests we will probably never find a “gay gene.” Sexual orientation is not about genetics, say the researchers; it’s about epigenetics. This is the process where DNA expression is influenced by any number of external factors in the environment. And in the case of homosexuality, the researchers argue, the environment is the womb itself. … Specifically, the researchers discovered sex-specific epi-marks which, unlike most genetic switches, get passed down from father to daughter or mother to son. Most epi-marks don’t normally pass between generations and are essentially “erased.” Rice and...