I know the 77% statistic is made up by feminists, but Wikipedia says :

By looking at a very specific and detailed sample of workers (graduates of the University of Michigan Law School) economists Robert Wood, Mary Corcoran and Paul Courant were able to examine the wage gap while matching men and women for many other possible explanatory factors - not only occupation, age, experience, education, and time in the workforce, but also childcare, average hours worked, grades while in college, and other factors. Even after accounting for all that, women still are paid only 81.5% of what men "with similar demographic characteristics, family situations, work hours, and work experience" are paid.[20]

Is this true? I want to not believe.