This is a useful discussion to have. To my mind an 'aggressive' research culture, timing issues related to parenting and the fragile egos of some men are social factors that can be changed and should be subsumed by our concern for lost potential. As a society, it is in our interest to nurture and encourage talented minds regardless of their gender in the sciences and engineering as much as possible. It is our collective loss when a talented scientist who happens to be a woman, leaves the field because of these concerns, especially when they *can* be changed. It's not in our interest to worry about the purported effects of cognitive differences, when young women are bombarded with negative stereotypes and told that it's not possible to be a social confident woman and be a scientist. Our highest priority should continue to be to stimulate and encourage potential, and combat societal pressures that are unhelpful and damaging to our collective interest.
It is our responsibility, as students who believe and understand the importance and relevance of science (and physics!) in human progress, to effect that change, even if it's only on an individual level. Whether it's as mentors (formal and informal) or someday as parents, aunts or uncles of young women, this is an issue worth fighting for not only for "PC" reasons, but for genuine, tangible societal benefit. Perhaps, just perhaps, a hyper-aggressive and arrogant research and classroom climate *isn't* the best way out there to do science. Perhaps, toning down egos, while offering a more welcoming environment to some young women who may be intimidated (but should NOT be), will also yield a more productive, effective experience for -all- students and researchers. Nothing's written in stone here. What's worked in the past is not necessarily the best way to do physics.
It's appalling to think of all the wasted talent over the past hundreds of years because of our own silly prejudices. Even if you're averse to PC-speak on equality, I'm arguing here that it's an issue of wasting talent and intelligence. I also sometimes think of my younger cousins who are girls, or someday if I have a daughter; I want the very best for them, and would be horrified if they forsake their talents (if they happen to be there) in physics because of intimidation or stereotypes.
And, fyi, I'm a guy. Perhaps I'm against the crowd on this one, but I enjoy dating women more intelligent than myself,.. makes life more interesting and the conversations stimulating