A little off topic here but it reminds me of an interesting point I read years ago. Men are supposedly more 'logical' than women and women are the weaker emotional creatures. I was reading a book about female serial killers and its interesting to note that women are considerably more likely to get away with murder. Reason being is men generally kill in fits of emotional violent outbursts while women generally are more calculated and planned (ie. logical).
Back on topic... I think while men and women's brains definitely work differently, there is that equality in regards to negative behavior. I wonder how much of women's restraint in regards to violence has been social programming. Many countries are still very much male dominated and while women are breaking out of that mould in many, there is still remnants of it. For example women still get paid less, women are still being expected in something like 95% of relationships to deal with housework even if both partners have full time jobs. And anyone who picks up a Dolly, or Cleo magazine can see girls are still being fed the idea they should be focused on looks, makeup, fashion, shopping and other ditzy crap. You wont find those magazines encouraging girls to educate themselves for highly successful careers.
I've also noticed a massive increase in violence among women and traditionally 'male' behavior from girls. Teenage girls in groups bashing up other girls for example. Its happening more and more often. Also women are becoming seemingly more predatory in regards to picking up and/or manipulating guys. I think all this is because views on what is acceptable for ladies is loosening up with the whole 'women's lib' thing.
Don't get me wrong... I am strongly opposed to discrimination and wish for real equality for women all over the world. I just think both sexes have their strengths and weaknesses and i think what we are raised to believe as acceptable has an impact on our personalities and actions. A child who sees their father beat their mother has a very high chance of following those patterns when they grow up. Girls who see that as children tend to end up in abusive relationships and boys who see it tend to be abusive themselves.
Not sure if its true or not but a friend also read that some studies have shown women actually think about sex more than men which blows another stereotype out of the water.
That ones still a mystery to me. I would also say that Estrogen is not as innocent as you would like to think. 
