Women as boss

In class when we talked about de Beauvoir philosophy on women, someone mentioned the stereotype of women being a "bitch". And we talked about how a woman usually is called this if she is strong-willed and aggressive. This made me think about an episode of That 70's Show when Jackie gets a job at a tv station and her boss is a woman. She comes back from work complaining how mean of a boss she has and Donna says "why is it when a man is a jerk he is just a tough boss but if a woman is the same way she is a bitch?" This is such a good question. Many times a woman will act just the same way a man would but it has a total different effect on each one. This is even true in the idea of sex. If a man has slept with a lot of women it is seen as an accomplishment but if a woman has slept with just as many men she is called a slut. What is it that makes females and males so different?