I heard an interesting theory on low female attendance in STEM this week: the fact that those fields are stereotyped as nerdy, "low prestidge" men. It keeps a lot of men, at least in the US, out of the field too. When I went through engineering school at least half of my classmates were from countries that have very different attitudes towards engineering.

I'm sure there's some data out there breaking out US STEM graduates by country and see how that compares to other fields like arts and sciences - that'd be a good place to start a conversation around whether or not some Western countries have a cultural / stereotypical problem.