There is no history of moral thought on transexualism. The surgery is a 40 year old thing. Granted, behaving in the other sex is not a new thing, but now it seems that it was natural for those people, not a volutary perversion, so the centuries of teaching need revamping, much like how original sin needs some revision in light of Darwin’s findings and the modern scriptural scholarship that shows Eden was meant to be myth, not history, and that Leviticus was as much cultural teaching as moral in order to preserve the Jewish nation in exile. We can chose to reject new fact, like the idiot Pope Pius IX or we can adjust where necessary.