One of the sad things about the state of sex ed is that this isn't taught in school. The interplay between genetics (homosexuality is at least somewhat heritabl

One of the sad things about the state of sex ed is that this isn't taught in school. The interplay between genetics (homosexuality is at least somewhat heritable) and environmental factors (each older brother a boy has from the same mother increases the chance he will be gay by about 40%). Also, this study and many others uses the term "men who have sex with men" not gay. These are two overlapping but different groups. Plus you need yo look at evidence that sexuality is a modern construct. The Kinsey scale and attitudes to sex in other societies (where men who have sex with men are sometimes considered a third gender or where its more a matter of taste/fancy than a rigid part of identity) would help people understand actual sexuality more effectively. What you end up with is some genetics, some epigenetics and some environmental factors creating preferences of various strengths. Those are then buried under a layer of socially acceptable behaviour. Which in turn is filtered through identifies ("I'm not gay, I just do it with my mate"). The point being humans are messy.