At the advent of World War II, BPW developed a classification system for women with specialized skills critical to the war effort and supported the formation of women's branches of the U.S. Armed Forces. While wage discrimination has existed in the U.S. since women and minorities first entered the paid workforce, its prevalence was not felt until the massive influx of women sought work during World War II. Immediately following the war, the Women's Pay Act of 1945 - the first ever legislation to require equal pay - was introduced in the U.S. Congress. It was another 18 years before an equal pay bill made its way to the President's desk to be signed into law.