To be honest, this is a dead horse by now. It has been shown time after time that the gender gap is due to differences in the market behavior of men and women. Women with master's degrees are paid less because they work less or work less well-payed jobs or are not as career focused. Women also control a large majority of discretionary spending in the household, so there is a large transfer of wealth from men to women. All in all, women work less and spend more money. What else could one wish for? Now, you could criticize gender roles in society and women's biological function as child bearers, and that is legitimate, but don't pretend that men have this conspiracy to pay women less. And there is a much more important pay gap to worry about, especially in the US, where CEOs earn an absurd amount of money compared to regular workers in their companies.