By Sheryl Jean, The Dallas Morning News

DALLAS — If you want to start a fight, talk about pay differences between women and men.

And then throw in politics just to spice things up.

That is what’s happening in Texas and across the country as equal pay takes center stage as mid-term elections heat up.

Texas Democratic gubernatorial nominee Wendy Davis recently rebuked her Republican rival, Attorney General Greg Abbott, for his opposition to legislation that would make it easier for workers to file a wage discrimination claim. State Sen. Davis sponsored the bill last year, but it was vetoed by Gov. Rick Perry.

Davis is one of several Democratic women candidates nationally hoping to mobilize female voters, who are a critical voting bloc. Candidates — from Maryland gubernatorial hopeful Heather Mizeur to North Carolina Sen. Kay Hagan — have voiced their commitment to fight for issues important to women, including equal pay, health care and domestic violence.

The numbers show that women working full time make less than men overall. In Texas, the annual median pay for women in 2012 was $35,453, or 79 percent of men’s $44,802 median pay, according to U.S. Census Bureau data. Nationally, the pay ratio of women to men was 77 percent.

Those figures are for all workers in all types of jobs and exclude certain factors, such as education, occupation and the number of hours worked. Studies show the wage gap narrows after considering such factors, but it does not disappear, leading many to think there’s a real problem.

The greater fear is that the gap widens over time, meaning women have less earning power and save less for retirement.

The focus on paychecks comes as more women participate in the workforce and more women are the main breadwinners here and nationally.

The question is why pay parity has not been reached yet.

“I think there’s no one answer, which I guess is why it’s a controversial subject,” said Sandra Black, a professor of economics at the University of Texas at Austin who has studied gender pay issues.

“Some people say the pay gap is not real,” said Catherine Hill, vice president of research for the American Association of University Women. “The pay gap is real; it’s just explained in different ways.”

Part of the pay gap can be explained by choices women make: Women are more likely to leave the workforce or work part time to become mothers and primary caregivers, ending up with less work experience.

Reports show the pay gap starts early and widens over time. Women working full time earned 82 percent of what men did just one year after graduating from college, according to a 2012 study by the American Association of University Women. Even after accounting for variations in choice of major, type of job and number of hours worked, 7 percent of the difference in women’s earnings to men’s could not be explained, Hill said.

Women also tend to work in lower-paying jobs, such as teachers, while men take higher-paying jobs in computer science and engineering.

The fact that a wage gap persists for women after accounting for differences has led some researchers to conclude that wage discrimination exists in the workplace.

“There’s evidence that discrimination exists, but that’s hard to prove,” UT’s Black said. “In most jobs, you can always say there’s something you’re not measuring.”

Bias is when two people who arguably are equally productive are paid differently, Black said. The issue is in trying to determine what is equal productivity, she said.

Some people may not be aware they have biases in the workplace, Hill said. For example, “people may think a woman is more likely to leave to have children, but men also may move for other reasons,” she said. “There’s no reason to expect that men will be better employees than women.”

Overall, women’s wages just aren’t rising fast enough to make a big enough difference.

Nationwide, women’s wages grew substantially from 1980 to 2000 due largely to increased education and more women in the workforce, while men’s wages were stagnant, according to a report by the Institute for Women’s Policy Research. Since then, women’s wages have not continued to grow.

Photo: Alan Kotok via Flickr