She mentions her field of STEM (mechanical engineering) has a particularly low percentage of women among its members, and cites another site. On that site, there is this interesting list: 39% of chemists and material scientists are women; 27.9% of environmental scientists and geoscientists are women; 15.6% of chemical engineers are women; 12.1% of civil engineers are women; 8.3% of electrical and electronics engineer…
Years later, when I was going back to college and trying to choose a major, I knew I wanted to do something with the built environment. I went through university catalogs and looked at what different majors entailed. I took "civil engineering" off the list pretty early in the process because of the requirement to take multiple calculus classes.
Women often do not have great math backgrounds. They may do fine in math up through middle school, but often start falling behind in math in high school. It is not clear if this is because of social factors or innate lack of ability. But it is a known phenomenon. So I would wonder if the ones where women are very seriously underrepresented are the ones with the most significant math requirements. If that doesn't check out, I don't know what I would look at next. But that is the first thought that comes to mind for me.