Following on from Catiette's excellent post, I just wanted to add a thought I had after having read it:
(full disclaimer: This may very well have been said already, but I gave up on the thread some time back, because I can't handle the word salad arguments for why we must believe that men can become women, and I would have completely lost my temper, and that wouldn't do anyone any good at all)
As a woman who has studied history, it suddenly occurred to me that women never had a gender (separate from our sex) because we never needed one. I'm generalizing here, because there always have been women who have pushed back against the restrictions of patriarchy, but, within the history of written record and therefore historical evidence, they are very few and far between.
Whether for good or bad (and I would argue for bad), women didn't need "gender" because we had no rights at all. Everything we were, wore, ate, created, and everyone we birthed, belonged to men. Even free women, even wealthy women, owned nothing that wasn't ultimately controlled by men.
We were a sex. We were the weaker, degenerate, malleable, useable, birthing sex. There was really nothing men needed from us except our wombs. Most men, including in the Church, through medieval times and beyond, believed that all babies grew from a seed that the man provided; a womb was just a vessel in which that child would grow.
Sex is all we were. We didn't need a gender to be able to prove that we had thoughts, ideas, intelligence, cunning, potential, or any kind of a future that didn't include servicing men in the continuation of the human species, because we never had, and we were never going to have, any existence outside the control of men.
It wasn't until we started pushing back against the constraints of the patriarchy (secular and religious) that we needed a word to define this new state of being, separate from what men defined us as.
I would argue that it started with tiny steps during the Enlightenment (only for women of independent means or male relatives who "indulged" them), continued during the early Industrial period, expanded rapidly during the mid-nineteenth century, closed down somewhat between 1890 and 1914, then exploded after the First World War. And we were still called "the female sex."
Most of us are aware of the rest of the story, through the Second World War, the Fifties, and the beginnings of Feminism, and, finally the term "gender." But I think the seeds of the idea for gender, as separate from sex, came about only when women began taking things to ourselves, and some very brave women, especially in the nineteenth century, had to risk everything in order to change the rules and laws so that we could keep what we had taken as ours. This is when we started to realize that although sex could never be changed, or used to improve our situation, gender could become something we could use to define the impositions and restrictions placed upon our sex.
And so it remains today, with sex immutable, but "gender constructs" which can be used, chopped and changed however society wants to. Or not used. But this has been what activists have been trying to claim, and take from us, because they can't take our sex.
This is all very Western history of course, and maybe it's all been said before, but that was what I thought after having read Catiette's post, and having been on the Sunderland Minster thread.
Does any of this make sense?