> If the percentage of female computer science graduates (as a strong proxy for the available candidate population) is 18% (Google for the facts and stats), how is every company to hit an idealistic goal of 50% representation?

Oh it can be done, it just requires reducing the number of male employees in one way or another. Everyone wants to believe the utopian ideal of perfectly-balanced ratios of employees can be achieved without someone getting the short end of the stick, but reality says otherwise.