"What proportion (of x ethnic group) would you like?" is a question that greatly devalues the contributions of the individual student. Would you say, "You're a great interview candidate, but we already have a tall guy,"?
She had a sterling high school record, but they wrote a rejection letter explaining that they already had a woman attending the institution.
The punch line, as it were, as I recall it, was that "a woman" did not mean one undergraduate woman, but just one, period.
So, she went to a much less prestigious and well-known school, majored in math, and ended up being a programmer instead of an engineer.
I am not sure if she was bitter about it.
And really we do it for college too. Except it is “we already have enough comp science majors”.