Gender wage gaps in 2004 are not primarily caused by discrimination against women.
Gender wage gaps are largely the result of work history, experience, industry and the choices women make. Examples would be three of my four very successfully employed Master's degree daughters in their 30s who are now temporarily staying at home taking care of their young children.
An example of the significant advances made by women in employment and wages is the annual follow-up of the graduates of the Wisconsin Technical College System. Universities and university systems like the University of Wisconsin System do not have comparable data for their graduates. University research on employment is largely hype about the importance of four-year graduates with no analysis of comprehensive hard data.
Women graduates from the 16 Wisconsin Technical College Districts in 2003 made up 12,589 (65%) of 19,358 graduates as compared to 6,745 (35%) men. The percentage of women graduates from the WTCS has increased significantly since the 1980s but has been more than 50% for at least the last 20 years. The percentage of women graduates nationally from American two and four colleges and universities is increasing significantly each year and will eventually exceed or be on a par with men graduates from higher education nationally in "most" academic and professional majors, if they do not already exceed men in 2004.