Homosexuality is not a social disease, nor does it defy nature. For those of you unaware there are a breed og chimps that live in the congo called the Bonobos that practise sex as a way of resolving issues, as well as for the hell of it they also practice homosexuality. If you dont beleive me here is the link to wiki about them.
http://en.wikipedia.org/wiki/Bonobo
oh I forgot to mention they and the Common Chimp are Humans two closest relitives.