I find it very curious that at high school level, it seems females outperform males in grades, and there is higher female participation/caring about the content

I find it very curious that at high school level, it seems females outperform males in grades, and there is higher female participation/caring about the content (participation is rarely voluntary in high school); but as soon as you go to university level (STEM in particular), participation rates do a complete switch in that a lot of STEM fields have a huge over representation of males.