I want to be careful here and make a distinction between the umbrella of gender variance (regretably misnamed as the transgender umbrella) and the experiencing of gender dysphoria which is a measurement of the disconnect one feels from birth sex. It's important to state that not all gender variant people are necessarily gender dysphoric which is a condition which can require intervention from the medical arena. In other words, there can be a whole host of reasons (including sexual) for expressing gender variance which need not be associated with dysphoria.
When it comes to dysphoria treatment, in my humble opinion, endocrinologist Harry Benjamin turned out to be completely correct when he classified his patients on a scale which ostensibly measured the severity of their gender dysphoria (or disorientation as he referred to it). It allowed him to place individual patients on a gradient from 1 to 6 which ranged from occasional cross gender expression to a full blown psychosexual inversion which required immediate attention. In this sense he was not dissimilar to Alfred Kinsey who also used a scale to measure the sexual orientation of his own patients in his studies penned in the late 1940's.
The concept of a spectrum is very elegant and helps us to explain both male to female and female to male transsexualism. Unlike the ideas of people like Ray Blanchard, it is a concept which is not at all disjointed.
Benjamin's empathetic approach and meticulous bed side manner are in stark contrast to what followed decades later, however we are now realizing all the more how important his legacy will become and how much it will forever be honoured for its pioneering efforts to treat trans people with dignity and respect while simultaneously promoting scientific knowledge.