Please no one smack me over the head with this if I get it wrong (it was 12 years and a lot f wine ago), but I did a history degree, and there was a really fascinating lecture on sex and gender paradigms through history.
In the medieval period, your humours determined your personality (sanguine, phelgmatic etc), and men and women were scientifically considered to have "one body" - the uterus and ovaries being an inverse penis and scrotum. Men would normally be considered to have one balance of humours, women another, but there was nothing to stop a man or woman having a typically more male or female disposition.
Yes, male traits were usually more valued, and yes, you would be considered a bit of an oddity for stepping out of gender norms, but that's how it was understood. (there were other implications - e.g. it was believed that unless a woman orgasmed, she didn't release eggs, so on the one hand, men wanted their wives to enjoy sex, on the other, rape victims were disbelieved if they got pregnant because they must have enjoyed it).
Then at some point it was 'discovered' that we have two different bodies, and at the same time, it was agreed that women's bodies were inferior, physically and mentally. This was part of the fundamental opposition to women having the vote.
Now I'm not saying it was better in the medieval times for women, but I certainly think the idea that we are all more separated by our individual dispositions than our sex biology rings more true to me!
I wish I'd taken that module (not that cultural and race history wasn't interesting), but because it was bloody interesting stuff!