Although the male-female ratio of undergraduate students, doctoral students, professors and Fields Prize winners in mathematics department has been rising all the way, the male-female ratio is almost one to one in terms of learning high school mathematics well.
Saying "girls can't learn math well" will make girls who are not good at math feel better: I'm not stupid, I'm not lazy, and as a girl, I shouldn't learn this. But this first pits the girls who study mathematics, and makes them bear greater negative hints and social pressure. Secondly, I also deceived myself: the corruption of women's image will lead to unfair treatment of all women sooner or later.