I have nothing to add to this discussion–everyone has said everything so much better than I could–but wanted to pop in to say how bucked up I am by such a civilized, polite and good-natured discussion of the issue!
This also occurred among the vikings and Teutons. Male priests of Freya/Frau Hulda lived as women. In return for this, the goddess would grant them mystical abilities. As a shaman’s role is to straddle the divide between the visible and the invisible, flesh and spirit, divine and human, life and death, shamans often lived in a manner straddle male and female.