It's definitely not genetic. Countless studies on identical twins have concluded that there is no link between these identical twins because the chances of having both identical twins be homosexual is right on par with the chances of any randomly selected individual being homosexual. I also have two good friends who are identical twins and one is perfectly straight, and his brother is gay.
You are shifting focus.
The question is not whether it is a "genetic" trait or not.
The question is whether it is a "disiase".
WHO has officially declared it to be NOT a disease.
NOT A DISEASE. PERIOD.
Plenty of historical evidence though.
O'RLY?
If you care to look at how the peoples of historical advanced civilations such as Rome or Greece... not long after they accepted homosexuality as the norm, the greek/roman family structures began to deteriorate and added to the other more commonly spoken about causes which you can find in history books.
In fact, this is so UNTRUE. http://en.wikipedia.org/wiki/Roman_Empire
Roman empire has undergone a total meltdown after it accepted CHRISTIANITY with all its CELIBACY NONSENSE. Off course, it was already a troubled state before christian takeover, but this just makes the popular claim of "ghey rotting away rome" not only a logical fallacy, but also a factual error.
note that I am not claiming that Christianity caused deterioration of Rome (that would be a logical fallacy)