http://latimesblogs.latimes.com/booster_shots/2010/02/gay-guys-make-great-uncles-maybe-thats-why-theyre-still-among-us.html
Evolutionary biologists have long scratched their heads over homosexuality in men: If there is a genetic component to male homosexuality–a view for which there is considerable evidence–then why has that gene persisted to this day? After all, if one were disinclined to spread one’s seed in places where it would result in offspring and extend your bloodline, evolutionary reasoning would tell you that genetic propensity would disappear.
And yet they live among us–sons, brothers, dads and uncles. Especially uncles.