To throw more scientific research in: a few years ago the University of MN psychology dept. did a "twins reared-apart" study. The results? In cases where one IDENTICAL twin is gay (and, 'reared-apart, ie. never had any contact with straight identical twin, or their parents - often they were reared on opposite corners of the globe), approximately 48% of the time SO IS THE OTHER TWIN. This is from a sample of, if I remember right, roughly 50 identical twin sets in which at least one twin is gay (again, reared-apart).

Basically, this study proved that the odds are definitely in favor of there being at least SOME genetic link, if not cause for homosexuality (I am in no way trying to make homosexuality sound like a disease or something) - in much the same way that there is a genetic link for intelligence, personality, etc. (all of which were also studied and proved in the same U of MN study, by the way).