"What I don't understand is why if there is a mismatch between body and brain we accept treatment is to change the body, not the brain"
I've always wondered this. It seems to be incredibly offensive, almost unmentionable, to transgender people to suggest it, though, and I don't know why. We know it's impossible to change the sex we were born as, but it is possible to work on our mental confusions and unhappinesses.
Wouldn't it be far better to start all over again with this - because it's all gone the wrong way, what with giving hormones to teenagers, binding breasts, pretending we can surgically create a body of the other sex - 1) encourage people to wear anything they please (and freely adopt all the other trappings of "gender") and 2) sympathetically give psychiatric? help to those with dysphoria to accept their bodies as they are, as we gradually change society so that eg a man in make-up and a dress is absolutely unremarkable.