There are a lot of things that feel perfectly natural that are environmentally induced. A single incident can influence your whole life, in small or big ways, but the same incident with another person's perspective may have no influence at all on him or her.
In my opinion, if you can "induce" homosexuality through child abuse or role model neglect, for example, the whole theory of genetics goes right out the window.
I didn't say that all homosexuality was bio related. I think it is a mix.