Equal pay for equal play? As women's sports become more popular, female athletes are demanding to be paid like their male counterparts.

• Author: Stoffers, Carl
• Position: SPORTS

The stadium was in Canada, but the crowd chanted "U-S-A! U-S-A!" The U.S. women's soccer team had just defeated Japan to win the 2015 World Cup--the team's third--and midfielder Carli Lloyd embraced teammates Hope Solo, Megan Rapinoe, and Abby Wambach. The four players pumped their fists in the air as confetti rained down on the field. Back home, an estimated 27 million Americans tuned in, making it the most-watched soccer match in U.S. history.

Yet if the four women had pooled the $75,000 they each received from the U.S. Soccer Federation for winning, it still wouldn't equal the roughly $400,000 each member of the men's team would have made if his team had won the same tournament. Because of that pay disparity, Lloyd, Rapinoe, Solo, and two other teammates filed a complaint with the federal government last spring. It accused the U.S. Soccer Federation of wage discrimination for paying women less than men, despite equal work--and more success--from the women.

"When we started to see the men's contracts and saw the differences in pay it really opened our eyes," says Lloyd, a captain of the women's team. "When you do the comparisons, it's alarming."

If the complaint is successful, it could result in the women receiving hundreds of thousands of dollars in back pay, and the federation could be forced to pay both teams equally. The U.S. Soccer Federation declined to comment while the complaint is under review.

The Gender Pay Gap

Gender-based wage differences are nothing new in the United States. U.S. Census Bureau statistics show median earnings for full-time female workers nationwide are 79 percent of what their male counterparts earn. The issue came up during the presidential election, with Hillary Clinton arguing that equal pay was "long overdue." (President-elect Donald Trump has said he supported equal pay, with some qualification: "You're gonna make the same if you do as good a job.")

According to experts, gender pay differences are partly a result of how America's workforce has evolved, both on and off the playing field.

"Historically, we've had a male-dominated workforce," says Angela Lumpkin, professor of sport management at Texas Tech University. "They got there first and established their salaries."

Lloyd and her teammates allege they have it much worse than female workers in general, earning just 40 percent of what the male soccer players are paid.

The fight for women's equality in sports accelerated after Congress passed the 1972...