Do we know what they are? No. But the dynamics between men and women are so damn different it's evident there must be a difference to begin with. Just because

Do we know what they are? No. But the dynamics between men and women are so damn different it's evident there must be a difference to begin with. Just because it's not proven and not certain 100% doesn't mean we can't look at it and go "yep, this really seems to work a certain way". There are no double blind tests done for parachutes.