Daniel Drezner is pondering women in science and technology: do they leave because they're pressured to, because they think it's unfeminine, or just because they'd rather do something else?
I actually found technology relatively family friendly, if only because women were such a novelty that companies liked having them around. On the other hand, it was definitely a boy's club; I experienced some really stunning sexual harassment during the years I was a consultant, not to mention having to sit quietly at lunch while my colleagues discussed the women they were checking out.
But ultimately I left not because of a hostile environment, or because I worried that it was masculinizing me. I left because I just didn't care as much as the guys I worked with. When I came in on Monday morning and people asked me what I had done, the answer was usually something like going to a club, or sailing. When they asked the guys I was competing with, the answer was more likely to be "I built a fiber channel network in my basement." It seemed likely to me that my career would suffer from competing with the monomaniacal, so I left to find something more in line with my obsessions.
But that's only my experience; I can't speak to anyone else's. Especially since the entire time I was a technology consultant, I only ever worked with two other women, and one of them left to have a baby two months later.