On somewhat of a tangential note affirmative action is an interesting issue.
Assuming the goal is to provide equal opportunity for those that were unlikely to have the same advantages as others through their childhood, I think making this distinction by race instead of socio-economic standing perpetuates a lot of racism. It suggests someone is disadvantaged simply because of their race. While it creates an ethnically diverse student body it doesn't create a class diverse student body (so it's a bit of a pseudo diversity).
Using a socio-economic standard you abstract away the race issue and give an advantage to those who have less money which has a stronger correlation to actually having less opportunity. This also creates a more diverse student body as well.
There is one very important reason it had to originally be done by race - the choosers in the original system were racist.
If admissions is racist then you can't do it by socio-economic standing because they'll just only pick whatever race they prefer. To make the switch you have to be able to determine that the choosers are no longer racist.
It's another hard problem, but I'm not entirely sure I understand the connection to this issue. If the comparison is that women should be given an advantage because they're disadvantaged technically I'd think that is exactly the sexism that's the core problem - and is unfair to the women who are really great.