Why are there so few women in math olympics (IMO and etc)? If this is also related to the low participation of women in the Olympics compared to men, I would like to know.
Why Are There Still Only Few Women in Science An interesting article you can find on Nytimes about why low number of women in science
I also found some studies that try to explain why women's participation in math olympics is low. They have shown that many women also believe the stereotype that women are bad at math. Women who hold this belief may be reluctant to compete in math competitions, so it probably makes up for this effect.
I sent some studies that I read and found relevant.