I've enjoyed reading this thread and thought I'd add my own perspective to the mix.
Gender identity depends upon three factors; (1) the physical morphology (penis or vagina), (2) the chromosomes/genes (X,Y=male, X,X=female), and the brain (males and females have distinct neural networks). In most cases these three factors are in agreement, however, they don't have to be in agreement. For instance, you can have a genetic male (X,Y chromosomes) who will have a defect in the SRY gene of the Y-chromosome. This condition will make the person appear as a normal female (with vagina, breasts, etc), however he/she will be sterile. They usually don't know they are genetic males until they question why they don't have a menstrual period and see a physician who determines that they are genetic males.
Similarly, researchers using magnetic resonance tomography can perform brain scans and see the neural networks in real time. Simply by observing the brain scan they can determine if they are seeing a male or female brain by the activity of their neural networks. However if they observe the neural network activity of a transgender person the pattern will somehow be between male and female. Crossdressing is a biological condition hardwired into the brain. http://www.sciencedaily.com/releases...0107082133.htm
The crossdressing spectrum covers a wide field and it should include TS. The extent that we pursue our crossdressing, and even transitioning, reflects the extent of our neural network's gender identification. What works for one may seem completely out of the question to another - why? Because our brain's neural networks are different.
Personally, i am content just being a man in a dress.
