> selection pool for women is smaller in STEM, therefore less women means less exceptional women
This is only true if you assume women in STEM are a random sampling. If you consider survivorship bias, it's quite possible that the cohort of women who persist are better, despite being fewer in number.
The same is also true for men, unless you start with the belief that the misogyny is a baseline factor that women have to deal with. But that's what this analysis is trying to figure out. Chicken and egg maybe?
This is only true if you assume women in STEM are a random sampling. If you consider survivorship bias, it's quite possible that the cohort of women who persist are better, despite being fewer in number.