It may be useful to bring up the concept of unconscious sex vs gender. The former refers to whether you feel that you should be in a male or female body. A (MtF) transsexual would tend to say a female body, often even early on in the process of self-realization, regardless of ambiguous or confused feelings over womanhood and so-called female identity.

In fact, I would say that it's the tension between unconscious sex and gender (which is, after all, at least partly a social construction) that produces uncertainty. The interesting thing is that, in the case of a transsexual, unconscious sex is a stronger driver than gender.

Multiple factors compete within trans people in order to pin down identity. I suppose it possible to arrive at a position of comfortable self-integration anywhere in the spectrum, but it seems to be more common for people outside the binary to live with some level of dissatisfaction. Maybe it's because they still wish to be cissexual, or perhaps having just a few intrinsic inclinations out of sync with an otherwise cissexual psyche is fundamentally unsettling.

In any event, what I'm suggesting is that determining gender isn't an either-or proposition. Rather, it's a matter of relative priorities and even choice in some respects. We tend to overload "gender" as if it were an all-encompassing concept. It is not.

Lea