We say we're completely different all the time and we've done it for so long that we believe it. But the fact that the Mars and Venus guy sold 50 million copies of his stupid book doesn't make it true or right. 

There is no personality theory that is based on gender. It's true that on the "Big 5" women rate higher for neuroticism (anxiety/fear) than men, but the reason is, women fear men in a way that men do not fear women. Does this fact affect the way each gender behaves? Yes. Does it confirm something about a woman's nature? No. It confirms something about a woman's environment.

I DO believe that men spend an inordinate amount of time proving to themselves that they are not women and that women are nothing like them. I think that's where some of these divisions come from. I have no problem imagining myself as a man and have always had a boy floating around my psyche. But most men don't want to be women. Witness the stupidity that erupted over the Fearless Girl sculpture.