Is the percentage of women in STEM low in all STEM degrees in the US? I'm Spanish and math and chemistry usually have a 50/50 or >50% of women here. Not sure if those are considered STEM at all in the US.
Our social constructions heavily influence how "Men and women, on average, differ significantly on career choice, likes, dislikes, and motivation," (from grandparent comment). In Spain and Italy and Portugal, math occupies a very different social role than it does in the US. In particular, it's not seen as so thoroughly unfeminine. This is one reason there are so many fabulous women mathematicians from Spain, Italy, and Portugal, and why they stay there rather than moving to the US for academic positions.
I think the GP has a point but sort of a weak understanding of what people are selecting for. We change the characteristics we find most important about many jobs to make them fit the gender roles our society has. It's not the act/job alone, it's the role in society. In Malaysia being a programmer is a job that doesn't require mythical powers, so it's close to 50-50 in gender split. In Italy being a mathematician does not stereotypically require brilliance, Asperger's, or general social ineptitude, so it's ok for women. Being a schoolteacher in the US has shifted from a prestigious starter job for educated men who could keep discipline, "a stepping-stone on [the] way to careers in the church or the law" (colonial times, 1800s) to a job for nurturing women who love children (today) [1]. And we can look at computer science: women went from being the original "computers" and programmers to being... not suited to it (?). Right, not interested. For innate reasons.
Yes math and chem are STEM. In my experience, women were found in greater percentages in the basic science and maths (required for pre-med) and in the life sciences which were geared more towards medical professions.
