WASHINGTON, DC - SEPTEMBER 09: U.S. Senate Minority Leader Sen. Mitch McConnell (R-KY) (R) and Senate Minority Whip Sen. John Cornyn (R-TX) (L) listen during a media briefing after the Senate Republican weekly policy luncheon September 9, 2014 on Capitol Hill in Washington, DC. Senate Republicans held its week policy luncheon to discuss Republican agenda. (Photo by Alex Wong/Getty Images)

Senate Republicans on Monday blocked for the fourth time a bill that would strengthen federal equal pay laws for women.

The Paycheck Fairness Act would ban employers from retaliating against employees who share salary information with each other, impose harsher penalties for pay discrimination and require employers to be able to show that wage gaps between men and women are based on factors other than gender.

The bill needed 60 votes to overcome a Republican filibuster and advance to a final vote on passage, but it fell short Monday by a vote of 52 to 40. Senate Democrats have brought the bill to the floor four times since 2011, and each time Republicans have rejected it.

"The wage gap not only hurts our families, it hurts the economy," Sen. Barbara Boxer (D-Calif.) said before the vote. "If it were reversed, I'd be standing here fighting for the men. It's not right."

Republicans say they oppose the bill because they believe it would discourage employers from hiring women, out of a fear of lawsuits. The GOP has accused Democrats of staging a "show vote" on the bill in an election year, knowing it won't pass.

"At a time when the Obama economy is already hurting women so much, this legislation would double down on job loss, all while lining the pockets of trial lawyers," Senate Minority Leader Mitch McConnell (R-Ky.) said before the last vote on the bill in April. "In other words, it's just another Democratic idea that threatens to hurt the very people that it claims to help."

Women working full-time in the U.S. earn an average of 77 cents for every dollar men earn, according to the Census Bureau. A small portion of that gap, economists say, is due to employers paying women less than men for the same work.