On discussing this with a feminist friend of mine, I had it pointed out to me that a large part of this may stem from the fact that I'm a heterosexual white male, in a heteronormative white patriarchy (if use of "patriarchy" will be permitted). And this reminded me of something from psychological anthropology - that identity is often more like grammar than some sort of object. When grammar is used correctly, we do not notice; it is when its rules are violated that our attention is drawn to it. I do not understand identity, but I think that much of its existence is the result of some sort of rupture - or a gap between what is normal in society and what is unusual. A "normal" person is not reminded of their weirdness, while a transgender person is, just like a black person might be in a white-dominated society, or an Irishman in Beijing. Overly simplistic perhaps, but I think this has something to do with it. Identity interests me because it baffles me.