I chatted about this lack of girls in STEM events with other parents during a social event thrown by our local organization for gifted children, and they confirmed my observations. They were talking how their girls are more interested in writing, art or music and also how they are more interested in the activities and events where individual competition is de-emphasized in favor of teamwork. But even then, many said that their schools' robotics or LEGO teams hardly have any girls, not even when female coaches are available.
I still wonder if this is some sort of American phenomenon brought about by mass media and reinforced by parents and teachers. When I was growing up in the former Soviet Union, participation in such events was a lot more equal. But it seems that here we have double standards where girls are not expected to be competitive, they are expected to be nice, helpful, and excel at teamwork. Don't get me wrong - I want Smarty to be helpful and kind, but I feel that we are shortchanging our girls when we subtly discourage competition, because "someone's feelings will be hurt." Participation in individual competitions (not just winning them) can lead to feeling of competence, confidence, and desire to improve. I really hope that more will be done to encourage girls to participate in events not explicitly marked "girls only", so next generation of girls grow more confident in their academic abilities.
Why do you think girls are less interested in STEM competitions?