In grad school at development brown bags, we had the following rule of thumb: you are allowed to ask a number of questions equal to your year in the program (I think we made the rule after I asked too many questions as an overly excited second year). I found this useful because it made the opportunity cost of question asking salient to ME, as the question asker. I had to ask myself: "Is this idea really good enough to spend one of my chits on it?"
It seems that the men at your seminar series have a rule of thumb of asking one question per seminar, while the women ask at every other seminar. Perhaps the men should think of giving themselves one chit/question per two seminars.