1. Epigenetics. 2. Most gays self identify as children before any sexual activity. 
Your belief on divine law is based on the pietousness of asexuals, not reason or evidence. It is stoic, not Christian. To be Christian it must show God as humble of heart, be easy to follow and a light burden. It should certainly not drive teenage boys to suicide for having to chose between being true to themselves or true to God. God does not ask for such nonsense.