I have a theory about gender which I'll try and explain.. just maybe it might not be liked, but oh well;..
I think gender identity only develops throughout life experiences, since gender roles only pertains to social behavior. I think if the human race wasn't so easily influenced, there'd be just as many boys that would want to play with 'girly' stuff as girls. I think humanity's influencability also explains how society could have come to develop gender roles as they are now. The fact that women become pregnant easily develops to establish a setting of the men having to take care of providing food and shelter because of women's temporal incapacitation by pregnancy. Since the man develops the expertise to provide through this, it is the most simplest outcome that he continues, and because of this the woman stays with the child. Just that is enough to develop a good part of the societal roles. Not only that, but simple things like the woman noticing her body become something that looks beautiful when growing up, as well as other small things, is enough to influence certain aspects of the societal role's becoming. Think about it, if you have something beautiful to work with, you're more inclined to work with it, and other aspects apply in different cases with different people.
I think in today's modern society, gender roles aren't just not needed, but they're also outdated. Every human, be it male or female, has its own personality, its own desires, and I feel everyone should be allowed to act anyway they desire as long as it doesn't harm others.
I think that throughout the influence of seeing the gender roles enacted, whether it's just seeing your mother put on make up, or your brothers play with army men, it triggers a response in your mind according to your personality and desires, and subconsciously associates your mental representation to those roles you see enacted... and this mental process deepens itself as you live more and become even more influenced by the societal doings, and deepens your mental representation into those roles as well as deeper attachment to that representation, as we become more in tune with our desires. For typical people, the mental representation will change as they change, but for other people, like tg, their personality and desires, if strong enough, will make it so their mental representation develops on its own, especially if the body seems to be developing contrary to it.
So as you develop, and your body seperates itself more and more from your mental representation, until the contradiction is just too great, and a great sense of division and contradiction manifests due to this. The person's attachment to their ideal may or may not be very great depending on the mental developments that person goes through, and if it's very great, that person may conclude that their body is wrong, and may or may not suffer greatly from this, depending on how much importance is intergrated/perceived in the body and mind synchronicity. Sometimes it's so great that it's virutally un-changeable, and the person needs to change their body in order to feel like they do have that synchronicity.
.. so..yeah, the theory is that basically there's no such thing as gender beyond gender roles(which are now obsolete) and the mental representation developed by one's mind through experiencing life and its influences, when experienced in contrast to one's personality and desires.
..