[johnbm]

Because computer science is a lonely pursuit, with long hours, requiring an obsessive focus on abstract problems. I saw women consistently self-select into biomedical applications and chemical engineering, away from the hard theoretical work like physics and comp sci.

On top of that, engineering is one of the fields which has the largest attrition rate amongst its students. It's clear that just thinking you want to be an engineer is not enough to succeed at it.

Add to that the fact that women are inundated with the message that they absolutely should go into STEM, and I think you have a recipe for disillusionment that merely shifts the attrition further down the pipeline. Which is exactly what we find: after 10 years, many more women leave the field than men.

I have a tremendous amount of respect for any woman that does make it in the field, but they've pretty much all been the kind of atypical go-getter personalities that other, more girly women, feel intimidated by.