There are numerous studies which claim that women earn less than men.
Fundamentally women and men choose to do different types of work. Several years ago the difference in wages between hairdressers and mechanics was touted as proof of wage discrimination. Both had similar apprenticeship times, but hairdressers (mostly women) earned less than mechanics (mostly men). Obviously they are comparing apples and oranges.
Given a choice between working in a safe air conditioned room chatting to clients about fashion all day, and working in a garage, and going home stinking of petrol and oil everyday, which would most people prefer? The job of hairdresser is preferable, and the market value for these occupations reflects that. It has nothing to do with whether a hairdresser deserves the same - that's just the operation of the free market.
Sometimes similar studies claim it's for the same work. Unfortunately all of these feminist studies are comparing apples and oranges. There are factors which simply cannot be measured. Men are less likely to take time off to look after children, more likely to be available for evenings and weekends, more likely to be under pressure from partners to earn more money (and therefore work harder), and less likely to take maternity leave.
Men and women operate in a marriage market which, rightly or wrongly, favors men who make more money, and women who are more attractive.
20 years of political correctness will not undo 5 million years of evolution. Feminists want equal money, without doing equal work.