Why are you trying to get women into medicine? Just to help the historically disadvantaged? Why don't you just let poor people in and not care about their gender?
Nowadays, you could probably get away with that because everyone has got over the whole "women's brains are too small and their wombs too big for logical thought to even be possible" idea. But when the (highly successful) affirmative action for women was brought in, that was still a major part of American culture that it was designed to work around.
Similarly with the race thing. The US fought a big civil war about whether people with dark skin were livestock or people and the losing side didn't actually change their mind just because they lost. So they needed laws to address that.