If women really did work for only 76% of what men earn, why aren't business owners taking advantage of this great opportunity in labor cost savings? In fact, this gap is closer to 94% and when all factors are controlled, 98% according to the following analysis that lists top college majors by genders, and pay and wage gaps by job classification (without all controls). 

http://www.payscale.com/career-news/2009/12/do-men-or-women-choose-majors-to-maximize-income 

Some women claim they are not free to choose their college major or job. Really? Most men would be happy scraping by on a few bucks doing what they love to do, but the do dangerous and high-paying work because if they don't, their mating opportunities would be next to non-existent. If women don't have a choice then neither do men.