April 12 is Equal Pay Day, and President Obama is reminding everyone that women workers should be given the same opportunities as men. “We don’t want some of our best players on the sidelines,” he said.

Economic equality for women worldwide has progressed, but stubborn differences in pay between men and women persist. The most recent Global Gender Gap Index reports that while more women work than in 2006, the average pay for women is only a little more than half that for men doing similar work.

Obama, in remarks at the home of the late suffragist Alice Paul, called on employers to make salaries transparent. He said he hopes that children who visit the building — a short block from the U.S. Capitol — will one day “be astonished that there was ever a time when women earned less than men for doing the same work.”