A contradiction in the liberal view of gender

[SaStrike]

In a liberal social geography class I took last year at uni, two principles about gender were universally embraced:

A) Gender is a societally constructed concept. The gender roles we take are artificial constraints, and we should not limit people by them.
B) Transgender people were born in the wrong one and have every right to change genders.

I have never taken a course/class like this before, but I see your point. If gender is societal/cultural constructed rather than biological and people should not be limited by gender, how can we be born into the "wrong" one?

Anyway I think this is interesting and I'm yet to do some more research into it.