"Women are around 20% of CS majors, physics majors, engineering majors, etc – but almost half of math majors" ...
"I was totally confused by this for a while until a commenter directed me to the data on what people actually do with math degrees. The answer is mostly: they become math teachers. They work in elementary schools and high schools, with people.
Then all those future math teachers leave for the schools after undergrad, and so math grad school ends up with pretty much the same male-tilted gender balance as CS, physics, and engineering grad school."
I found https://www.aps.org/programs/education/statistics/fraction-p...
Vs
https://www.aps.org/programs/education/statistics/womenmajor...
Over 40% undergraduate degrees go to women, while less than 30% of doctorates.
Science Magazine, "Expectations of brilliance underlie gender distributions across academic disciplines", vertical axis is PhDs, 2011 numbers.
If nothing else at this point I think we can put a bullet in the "they just want to be math teachers" hypothesis.
I have absolutely no idea whether that matches reality for enough people to make any kind of a difference.
Unless math is "warmer" than CS --- it isn't --- this explanation doesn't hold much water.