"Much of the decline in the pay gap that occurred in recent decades has been because women have closed education and experience gaps. In fact, since women have increasingly become our most skilled workers, after accounting for education, even more of the pay gap is unexplained. In fact, once we hold differences in men’s and women’s education constant, the pay gap actually widens today; 20 years ago taking account of differences in education narrowed our estimates of the pay gap. The gender pay gap tends to rise with education, with the smallest differences between the earnings of men and women with less education and the biggest gaps among those with advanced degrees. The pay gap among
women and men with professional degrees is currently about 67 cents."
https://www.whitehouse.gov/sites/default/files/docs/equal_pay_issue_brief_final.pdf