Humans are Animals. Homosexuality in Animals of all species is normal and natural. We are born the way we are born no choices involved. Doesn't matter if we're Heterosexual, Homosexual, or whatever. There are many different theories as to why but one of the more common ones is that Homosexuality is Natures Birth Control. It's just one of those things we probably won't ever know. Also, Incest and Cannibalism exist and take place in the Animal Kingdom, primarily amongst other Animal species but the concepts of 'Right' and 'Wrong' are Human concepts. No other Animal has evolved enough to grasp them. One day, perhaps they will. Its just too bad it won't be in this Lifetime.
Myself and Science.