@Danoff The problem is you are neglecting all the valid scientific data and research that has been done on all of this, especially in regards to Chromosomes (not everyone in the world has the correct chromosomes for their physical sex), and even how a fetus is formed in the womb. Sometimes there can be a mismatch between the embryonic hormones at specific development points in prenatal development. Or even our mother having an insensitivity to certain hormones, or even becoming immunized to certain antigens within the body that are needed during pregnancy. These things affect how a fetus may develop. These things can and do lead to physical changes in prenatal brain development, and there have been studies to show that there are genuine physical differences in a transsexual/transgender persons brain before any cross-sex hormones are taken. Which goes to show that the whole 'gender' thing may be more physical than mental. The biggest thing is the fact that the genitals and brain form at 2 separate points during pregnancy, and sometimes there is a misalignment between both.
https://www.newscientist.com/article/dn20032-transsexual-differences-caught-on-brain-scan/
http://www.scientificamerican.com/article/is-there-something-unique-about-the-transgender-brain/
http://www.wsj.com/articles/SB10001424052702304854804579234030532617704
So as you can see, it is not as straight forward as you might think. And this is the reason why Doctors no longer try to treat the minds of transsexual individuals, but rather treat the body. Back when they used to treat the mind, and I use the term loosely. They used such things as lobotomy's, shock therapy, psychiatric drugs and institutionalizing people. A lot of the treatments often resulted in brain damage, and even in the worst case scenarios, death.
The problem here is that you can not treat the mind, if the mind is physically different in the first place. As I have shown above, genuine research has been going on in regards to the brains for male, female, and transsexual brains.
There are also other things throughout history, things that show the human race used to be much more knowledgeable and accepting on the whole 'gender' thing too. Such as in Ancient Greece, where some gods where considered to be both male and female, and some even as intersex or hermaphrodites.
Take Hermaphroditus for example:
http://www.mythindex.com/greek-mythology/H/Hermaphroditus.html
This is also a good article to read:
http://transascity.org/the-transgender-brain/