You're missing the point that there is a positive feedback loop at the source of the problem. The reason that women (or minorities for that matter) don't get into some fields of STEM is because there are no role models that tell them it's a good idea to do so. So there is a chicken and egg problem, and the only way do break the cycle is to give priority to such minorities. Is it fair to the members of the majority? Perhaps not. But in the end, I believe, it will justify the investment. Consider it a small price to pay for the millennia of oppression.