Teachers: Female versus Male

I always wondered why most teachers are women (and only a small portion is men). Is this profession dominated by females because of the traditional values, or is there something deeper encoded in our bodies that makes women better suited to be teachers? Do women have more patience, are they more caring? Is there something innate in women that they want to have children around? Are they better teachers?

When I went to school, in elementary and junior high, I only had female teachers. In high school (and university), however, most of my teachers were men. Why does the male teacher prefer to teach higher grades, older students?

In the twenty first century, when men and women are equal, there is a weird inbalance to our wonderful profession. What's up with that?