Gay Rams provide a difficulty for Homophobes

If Rams are homosexual and scientists studying this phenomena see that the rams 'Homosexuality' is caused by a combination of structures in the brain and chemicals in the blood, how can any Christian say in conscience that homosexuality is CHOSEN.

Further, if it is not chosen, it cannot be sinful for sin is defined as wilfully missing the mark, that is, CHOOSING to miss the mark.

Perhaps I could be enlightened then?