House Democrats easily passed the Paycheck Fairness Act on Wednesday — their latest in a long series of attempts to make sure women and men are paid equally. The final vote was 242-187. Democrats were joined by seven Republicans.

To give you a sense of how long bill author Rep. Rosa DeLauro (D-CT) has been fighting for this cause, she first introduced the bill in 1997.

“Very simple concept: Men and women in the same job deserve the same pay,” DeLauro told Vox. “It used to be this was the fringe; it was a women’s issue, ‘Why do we have to deal with it?’”

A gender pay gap has long existed; women who work full time in the United States make, on average, 82 cents for every dollar their male counterparts make. And data from the Bureau of Labor Statistics shows the gap has actually widened in the past four years.

House Democrats last passed DeLauro’s bill when they were in the majority in 2009 (it failed the next year in the Senate). Now back in the majority, they have a rare opportunity to pass a bill that has struggled to gain momentum in both chambers when it’s come up. Even though DeLauro and labor experts say a pay equity bill should be bipartisan, the Paycheck Fairness Act has languished out of the spotlight when Republicans have been in power.

Democrats are hoping the momentum of the #MeToo movement and a historic number of women in Congress will give this idea new life.

“This is historic. Rosa has been introducing this bill forever,” House Speaker Nancy Pelosi told the House Democratic Caucus on Tuesday, according to an aide present. “But public sentiment — public, social media, and all the rest — with help us with this.”

What’s in the Paycheck Fairness Act

The Paycheck Fairness Act essentially works to close loopholes in the landmark Equal Pay Act of 1963, which required that men and women receive equal pay for equal work.

As Vox’s Alexia Fernández Campbell wrote, that bill didn’t exactly work as intended. Progress has been hampered in a number of ways:

There are several reasons for the pay difference. Women are less likely to negotiate pay, and more likely to be penalized when they try. They are also more likely to choose career fields that pay lower salaries and are often pushed out of the highest-paying professions in the country, which reward workers who put in long hours — schedules that disproportionately hurt working mothers. But after taking education, occupation, and work hours into account, researchers say that discrimination could explain about a third of the pay gap. A 2013 study by the American Association of University Women found that women get paid 6.6 percent less than men in their first jobs, even after considering factors such as job location, occupation, college major, and number of hours worked.

The Equal Pay Act says employers can’t differentiate salary based on gender unless a number of factors — including seniority, merit, and work level — come into play. On its face, it makes sense; a new entry-level employee would not be paid the same as a higher-level employee with more experience.

But over the years, women found out they were making far less than male colleagues with the same experience and job titles. The most well-known example is Lilly Ledbetter, who sued her employer Goodyear Tire after finding out male managers with less experience were getting paid more money that she was as a female manager.

Ledbetter’s crusade resulted in the Lilly Ledbetter Fair Pay Act, which President Barack Obama signed into law in 2009. That law changed the Civil Rights Act so that workers could sue for fair compensation up to 180 days after receiving a discriminatory paycheck from their employers — rather than when the salary decision was made.

DeLauro’s Paycheck Fairness Act tries to push back on lingering inequity in three key ways. Perhaps most importantly, it would ban employers from asking candidates how much they made in previous jobs. It would also get rid of employer rules that keep workers from talking about their salary information, so that women could ask how much their coworkers are making and find out if they’re underpaid. Third, the bill would require employers to be much more transparent about how much they’re paying workers. Employers would have to share salary data with the Equal Employment Opportunity Commission, so that body could watch out for potential discriminatory practices.

As Fernández Campbell noted, that’s gotten significant pushback from businesses that would like to keep that salary data private. And DeLauro said she’s heard complaints in the past from male lawmakers asking why they had to deal with a “women’s issue.”

“Women self-select to get less money! Those were the arguments I heard,” DeLauro said.

But her bill doesn’t get at another important root cause of the gender pay gap: the economic impacts of motherhood. As Vox’s Sarah Kliff wrote, Princeton University economist Henrik Kleven found that mothers in Denmark (a country with a robust social safety net) saw their earnings take a significant hit after they had a child. Kleven compared the salaries of mothers to childless women and to men and found that “childbearing accounts for 80 percent of the gender wage gap in Denmark.”

As Kliff wrote:

Kleven finds a sharp decline in women’s earnings after the birth of their first child — with no comparable salary drop for men. The cumulative effect is huge: Women end up earning 20 percent less than their male counterparts over the course of their career. His study is among a growing body of research that suggests what we often think of as a gender pay gap is more accurately discussed as a childbearing pay gap or motherhood penalty.

Why it’s taking so long for Congress to do something about the gender pay gap

It’s the 11th time DeLauro has brought up this bill, and its second time passing the House of Representatives.

A number of things have hampered the bill’s progress, most notably the number of years Democrats spent out of the majority. But other impediments include delays while the courts figured out how to interpret the original 1963 law, according to Vasu Reddy, senior policy counsel for the National Partnership for Women and Families. Many judges interpreted the clause “any factor other than sex” in the 1963 law very broadly, she added.

“Problems don’t become apparent until you’ve had these bad rulings by the courts,” she said. “Civil rights evolved over time. I think there’s just been more awareness of different issues around equal pay.”

DeLauro, Pelosi, and other Democrats recognize the time is ripe to press the issue again. Equal pay for equal work is having a renewed moment, especially in the wake of the #MeToo movement and high-profile Hollywood actresses going public about getting paid far less for big films than their male co-stars. But the problem is far more widespread, disproportionately hurting female and nonwhite workers.

“We are in a different environment,” DeLauro said. “We’re looking at the intersection of where the public is on men and women and the workforce, and we’re looking at a body that is over 100 women who are here. Equal pay for equal work is now the center of public discourse today.”

It’s unclear whether the bill has a path in the Senate. But with the most diverse House class in history, advocates are feeling optimistic that something can get done eventually.

“I think there have been gaps in understanding around women’s experience that this new and diverse Congress can begin to close,” said Victoria Budson, executive director of the Women and Public Policy Program at Harvard University’s Kennedy School.