+(With the understanding that psychology is complicated and there's more to be said about what "as a first approximation" is even supposed to mean, but I need a few paragraphs to talk about the simple story before I can get to that.)
+
+The idea is that male-to-female transsexualism isn't actually one phenomenon; it's two completely different phenomena that don't actually have anything to do with each other, except for the indicated treatment (HRT, surgery, social transition).
+
+In one taxon, the "early-onset" type, you have same-sex-attracted males who have just been extremely feminine (in social behavior, interests, _&c._) their entire lives, in a way that causes huge social problems for them—the far tail of feminine gay men who end up fitting into the world better as straight women. _That's_ where the "woman trapped inside a man's body" trope comes from. This one probably is a brain-intersex condition. [TODO: cite that from Brown's bibliography]