WASHINGTON (MarketWatch) -- Women constitute more than half of registered U.S. voters, and issues close to their hearts and wallets reveal key difference in the platforms of Sens. Barack Obama and John McCain.

Last week, in the middle of presidential campaigning that has focused on the bleeding economy, a group of more than 30 economists issued a report card for Obama and McCain on their stance on 10 issues such as pay equity and paid family leave.

The criteria that the economists used reflects the view that the government has an appropriate role to play in supporting economic security, and that some individuals cannot achieve success without some support, according to Vicky Lovell, acting research director with the Institute for Women's Policy Research. Nancy Folbre, a noted feminist economist and a professor at University of Massachusetts Amherst, chaired the group, and said its intent was "pretty nonpartisan."

In the end, however, the report came close to damning to McCain:

"It's not unfair to describe McCain as a firm enemy of many measures that would bring progress for women, while there is hope that under an Obama presidency, their situation could advance substantially," a statement from the group's vice chair said.

Obama came out on top, with an overall grade of "B," while McCain received a "D," according to the Economists' Policy Group for Women's Issues. With the ongoing disparity in pay between men and women -- last year women's median weekly earnings for full-time wage and salary workers were $614, or 80% of men's $766 -- it's no wonder that economists are concerned about women's financial health.

Given that in the last presidential election 54% of voters were women, they should carry some weight. Women were also more likely to be registered than men (74% to 71%) and more likely to vote (65% to 62%). It seems that the parties are beginning to catch up to the voter population -- this presidential race produced the first woman on a GOP ticket, as well as a historic battle between a woman and an African-American for the Democratic nod.

Lovell said the report card on women's issues reflects a key difference between Obama and McCain's philosophies about how individuals should access help.

"McCain sees it to be entirely an individual's responsibility -- if a worker needs more flexibility at work and doesn't have it, they should find a different job," she commented. "Whereas Obama recognizes that they can't get a job with more flexibility, that there aren't enough jobs available with flexibility."

Pay and employment equity

When it comes to pay and employment equity, the economists gave Obama a "B" and McCain an "F."

Among other actions, to earn an "A," economists said the candidates must support a piece of legislation named after Lilly Ledbetter, a retiree who had worked for Goodyear Tire & Rubber Co. for almost two decades before an anonymous tipster informed her she was paid less than male co-workers. She sued after she learned of the disparity, but in a narrow interpretation of the Civil Rights Act, the Supreme Court decided that Ledbetter had waited too long to file a charge because she did not complain within 180 days of when the discriminatory pay decisions were made.

The Ledbetter legislation would amend the Civil Rights Act by spelling out that each new paycheck could be counted as a discriminatory act, opening a new window to file charges after each and every paycheck. The legislation was blocked in the Senate earlier this year. Obama voted to move forward with it, while McCain didn't cast a vote, but has said he opposes the bill because of litigation concerns -- a stance that hurt his grade. Obama didn't get an "A" because the economists said his pay-equity programs stop short of providing a "comprehensive approach" to reduce employment and pay discrimination.

Diana Furchtgott-Roth, director of the Center for Employment Policy at the Hudson Institute, a conservative think tank, backed McCain's view, and said that the Ledbetter legislation would just be a boon to trial lawyers.

"It would impede opportunities for women because it would mean that each woman when she is hired would carry with her the potential for litigation decades after the hire," Furchtgott-Roth commented.

Paid time off

When it comes to paid time off, Obama earned a "B+" and McCain a "D." To earn an "A" candidates must: advocate comprehensive paid family leave; support requiring employers to provide vacation and sick days; and support expanding the unpaid Family and Medical Leave Act.

"The vast majority of developed nations guarantee paid sick days and paid vacations for most employees," the economists wrote. "Absent these provisions, many financially strapped employees cannot take time work to care for either themselves of their children when illness strikes."

The economists fault McCain for not supporting an expansion of the unpaid provisions of Family and Medical Leave Act, and for not supporting federal legislation to require paid sick days for most workers, among other issues. Obama does support an extension of the Family and Medical Leave Act, and proposed legislation to require most employers to provide up to seven days of paid sick and family care leave.

Why is this a women's issue?

"Because of the number of mothers that are in the workforce now, and how few children have a parent at home full time," Lovell said. "The reason it's so important is that if a child is sick and a parent needs to take time off, a lot of workers face losing their job or losing their pay."

Furchtgott-Roth said mandating paid time-off benefits would make women less desirable hires because they would come with a "higher price tag" than men. "The reason why women are so successful is because companies don't have higher mandated benefits for them," she added.

Retirement security

On retirement security, Obama earned a "B," and McCain a "D," according to the economists.

To earn an "A" the candidates would have to oppose privatizing Social Security and support expanding subsidized savings plans for low-income adults, among other stances.

"Older women rely more on Social Security because they have fewer sources of income and fewer assets," Lovell said. "For women to be economically secure in retirement it's critical that there be some strong safety net."

McCain is "hard to pin down" when it comes to Social Security, according to the economists.

"McCain's past support for proposals that would privatize Social Security make his current plans suspect. ... He promises to work with Congress to put the system on a sustainable basis, but does not offer any specific proposals," according to the report card.

The economists gave Obama a high mark because he has "consistently" opposed privatizing Social Security, and has plans to provide a retirement savings subsidy for those earning less than $75,000 a year, among other proposals.