Women, men and science

Fewer women study Math or Science at universities than men do. Now there may be a genetic cause.
But when it comes to women I know, I see another reason. I know quite a bunch of both women and men who are very gifted at Math or Science. But while most of the men consider it natural to study the matter, the women mostly don't. Either they choose a related field, but some deemed more suitable for women (e.g. teaching Math - most of Math teachers I know are women) or choose an entirely different school, as (e.g.) Matfyz is just for mad mathematicians, isn't it...