Androgyny by Garbage. Just listened to it. It's not really about tgirls but I imagine most of us here are fans of androgyny. And with lyrics like these:
Boys.. Boys in the girls room
Girls.. Girls in the men's room
You free your mind in your androgyny
Boys.. Boys in the parlour
Girls.. They're getting harder
Also: sex.
http://www.youtube.com/watch?v=aGcXEEo1HAY&NR=1