Research on being Gay

I recently stated an opinion that being gay was genetic. My brother took me task over that, stating that my opinion was over simplistic.  I agree, it may be, as nature and nurture are not so easily defined in any situation.

I'd like to give some more research for anyone who'd like to learn more.

BYU Professor Bill Bradshaw on a Biological Origin of Homosexuality" (ref. http://mormonstories.org/?p=1158)

 animals displaying homosexual behavior: http://en.wikipedia.org/wiki/List_of_animals_displaying_homosexual_behavior

hemaphrodite (male/female) creatures:  http://en.wikipedia.org/wiki/Hermaphrodite

 hemaphrodite Leopard slugs engaging in 'perverse' sex:  http://www.youtube.com/watch?v=FhVi4Z6CjZk

What prompted my response was a comment made by the second highest leader in the LDS church who said that god would not make a person gay.  What is interesting is that he has made animals gay, animals and humans hemaphrodites, and many other things.  

Is there just one cause of sexuality, either straight or gay? I don't know, but if we question how a person is gay, we must also have to question how a person is straight.
http://www.youtube.com/watch?v=QJtjqLUHYoY