Boys with older brothers more likely to be gay
This is truly fascinating. For each older brother a boy has, his chances of being gay increase by a third. (For the record, I'm the oldest of two boys, with a girl in the middle.) Actually, the older brothers link was already established in previous studies, and was written off by those determined to believe that sexual orientation is not inborn with the "explanation" that family dynamics affected the psychological development in boys in such a way as to influence their sexual orientation (and of course the truly loony stuck with their ever-unproven, logical cul de sac "it's a choice").
What's fascinating is that a new study by the same man, Dr. Anthony Bogaert of Brock University, shows that this pattern only exists in brothers who are biologically related; in brothers who did not share the same biological mother, there is no link between fraternal birth order and sexual orientation.
The birth order thing kind of lends credence to my theory (shared of course by many others) that a non-heterosexual orientation could very well be a means of natural population control; as the more sons you have, the more necessary some kind of population control becomes.