But, if you hire more women than men to fix the skew, you're going to end up with more younger women in the department than men. Once the ratio has been fixed you return to free hiring, 50-50 or whatever is considered fair at the time. Years down the line all these women you hired to fix the ratio start retiring. Your ratio drops precipitously and you start hiring women again at a higher rate. This pulse continues, every 30, 40, or 50 years, it can converge or diverge depending on what the actual ratio of gender is in the hiring pool.

By purposely hiring more women you are forcing the ratio away from it's natural state, and you will have to continue poking and prodding the numbers to continue being PC.