In many respects this sounds like it is boiling down to the nature or nurture arguement. But why can't it be nature AND nurture?
For example my wife and sons are of Indian (Native American if you prefer) descent. We know through science that some Indians are genetically pre-disposed to alcoholism. But that is no guarantee. whether or not that pre-disposition comes to be fact will be dependent on the choices they make in life.
Heart disease runs in my side of the family. That means I have a greater chance of having heart disease in my future but again it is not a guarantee. The number of big macs consumed will also play a role in this.
Whether you take the bible literally or not, the point of the Adam and Eve Creation story is that sin is a matter of choice. And our choices, whether good or bad, positive or negative have a far reaching impact on not only our lives but the lives of many others, just as the choices of Adam and Eve had great consequences for all of mankind. I believe this is what Rooster7 is referring to when mentioning how children are raised that may "push" them in the direction of homosexuality.
kwc57, I believe that choice may be a bigger factor than you may notice although the choice may be more subconscious and thus gets confused with inborn instinct. Why?-because inborn instinct does not explain bi-sexuality, where a person like to have sex with both genders. It also does not explain other types of sexual activity that I will not describe in detail here for obvious reasons.
I have read of programs (one called Project Exodus) that have had some success in helping men "become" heterosexual again. This of course leads me to question this idea of inborn. Remember, we hear the hue and cry of inborn homosexuality form the gay community primarily. Why?-perhaps it is becasue if this concept were true then a gay person does not have to face the consequences of ones' choices.