What makes us tick?

I often wonder what makes a Transgendered person tick... Is it a biological need, or is it all in the mind? More than likely it is a combination of both. For some of us, we are disguisted with out male parts, for other we are very happy being just who we are. That leads to the next question.. Who exactly am I? That is the question that I find I ask myself more and more lately. After watching Transamerica last night, I am thinking about it yet again. I am realizing that I have only started on my journey when yesterday I thought i was reaching the end (or at least the middle). I am male physically and have no desire to change that, yet there is that part of me that is Heather that is taking over more and more of who I really am. I find myself wearing camisoles, women's jeans & slacks, etc. on a daily basis as part of my male mode (drab) dress. For the most part people don't notice or care, which is good, because I find these clothes so much more comfortable. I am finding that the male and female selves are melding into one as time goes on. There used to be a definite discinction between the two, but the further down the road I progress, the more the two become one. The lines are getting blurred, and I am liking it. I started out as the guy in lingerie who did it for the sexual fulfillment, and have progressed to the point where I no longer feel that need. I dress in whatever happens to be comfortable for the occasion. I am finding it harder to separate the two and my wife relly is a trooper. She puts up with my moods as they strike me and usually doesn't say too much about it. Where will it end? I don't honestly know. The one thing that I have discovered is that as I progress along, I discover more aobut myself than I knew before, which opens up a whole bunch of new questions.