Much of the 27% pay gap between men and women is not outright, easily identifiable discrimination anyway so it doesn't really have much to do with contractual rights of employers. Its the result of a complex set of factors including behaviors of employers, bias, the difference in behaviors and preferences of women and men in choosing jobs and balancing life, family, and work. etc, gender based cultural values, and educational choices made early in life.
"But switching to a fully adjusted model of the gender wage gap actually can radically understate the effect of gender discrimination on women’s earnings. This is because gender discrimination doesn’t happen only in the pay-setting practices of employers making wage offers to nearly identical workers of different genders. Instead, it can potentially happen at every stage of a woman’s life, from girlhood to moving through the labor market. By the time she completes her education and embarks on her career, a woman’s occupational choice is the culmination of years of education, guidance by mentors, expectations of parents and other influential adults, hiring practices of firms, and widespread norms and expectations about work/family balance held by employers, co-workers, and society (Gould and Schieder 2016). So it would not be accurate to assume that discrimination explains only the gender wage gap that remains after adjusting for education, occupational choice, and all these other factors. Put another way, we cannot look at our adjusted model and say that discrimination explains at most 13.5 percent of the gender wage gap. Why? Because, for example, by controlling for occupation, this adjusted wage gap no longer includes the discrimination that can influence a woman’s occupational choice."
What is the gender pay gap and is it real?: The complete guide to how women are paid less than men and why it can’t be explained away | Economic Policy Institute
