I suppose it all depends whether he would have continued to live happily as a woman he hadn't discovered that he wasn't one. Yes, I know that's impossible :D We could never know, I suppose.
My life is a constant interplay between my free will, my nurture/social conditioning, and my nature/genes. I'm not aware of it at the time, of course, but when I reflect on my actions I can sometimes see them at work. So long as free will is in there, I don't think I'm too worried about arguments about which is stronger. Hmmm, or maybe I am.