Homosexuality is widespread among animals, and it’s present in every culture we’ve looked at. All of which suggests that it’s in some way innate to the human species. But figuring out what “innate” means is a real challenge when it comes to a complicated suite of behaviors like sexuality—behaviors that are also heavily influenced by culture.
Studies of twins have suggested that genetics can influence homosexual behavior, accounting for roughly 20% to 30% of its frequency. But attempts to find specific genes that mediate this influence have come up empty. Now, an absolutely enormous study has found a number of genetic sites linked to homosexual