Feminists

I've often noticed this phenomenon through-out my life. In college I had many courses that were question-oriented and often the women in the class refrained from participating in the public discussion. This happened in classes with male or female instructors. I really noticed it when I was working in retail sales management- we often had break-out disussion sessions and sales training, but the females in the group did not have a proportional input due to lack of participation.
I don't think that most men desire to shut women out of the conversation through thier style or forcefulness in public speaking, at least it has never been my intention. I have been accused of intellectual misogony or bullying through public speach before, but it always turned-out to be a problem with my style of presentation and the confidence I displayed in my conclusions. The last thing on my mind when I am articulating an opinion or suggestion is the demeaning or trivialization of the women in the class room or board room. I am simply trying to convince the listener (male or female) to agree with my propositions and conclusions, and one way of convincing people is through confidence in yourself and your opinions and the display of that confidence through body language, speech inflection and tone and a wide body of knowledge about the subject.
I have raised my daughters to be the ones in class that speak-up and ask questions, and they revel in thier ability to silence "dudes" with thier command of the language and breadth of understanding in thier subjects. Most "dude" types are scared of my daughters and thier independant attitude and abilities.