Are you basing this on personal observation, or some documented studies, research etc?

I disagree with you completely, but I'd like to know on which specific grounds I should debate this topic with you.

EDIT: Just to be specific, I think that individuals will have "totally different social behaviours, instincts, communication styles, interests and temperaments". You can't just say "Males and Females", as you could just as easily insert any two discernible groups into that sentence. Inuits vs. !Kung would fit the bill just as well. Males and Females aren't defined by their gender, but by all the other things that make up their individual personalities.