Researchers at the University of Maryland in College Park and the University of California at Los Angeles reviewed 35 years of data from some 2,200 women born between 1944 and 1954, and found that women who had kids in the early- to mid-20s or even younger didn't fare as well economically as those who delayed. [...] this new study, presented by co-author Joan Kahn, a sociologist at the University of Maryland in College Park, finds women who got more education and job training before having children don't experience that so-called "penalty." [...] "Women who delay childbearing end up as successful economically as women who didn't have children, and we look at it basically throughout their adult years - well into their 50s," she says. [...] The point, she says, is that women who are younger when they have kids and attempt to get back into the workforce later may not have that up-front investment in education and training, which those who have kids later benefit from. They earned equivalent wages and had higher status occupations just like women who were childless.Now let us take a look at the wage gap for women, factoring in marriage and children:
Never married women without children make 117% of what their male counterparts make Another article with some interesting facts:
Never married women make 94,2% of what their male counterparts make 
Childless women make 90% of what their male counterparts make 
Recently, the conservative American Enterprise Institute announced the virtual death of the gender gap in wages--citing entry-level figures. At that level, women make 98 percent of what men do. But the institute failed to announce that it was only comparing the salaries of young workers. [...] Today, the gap in hourly wages between women with and without children is greater than the gap between men and women.What is going on is crystal clear and you don't have to be a rocket scientist to understand this. As long as women are the ones doing most childcare, this won't change. I assume empowering fathers will do more to the wage gap as every other legislation passed is trying to do. I wonder when then legislators will understand, but it seems to me this isn't going to be anytime soon.
While the hourly wages of women without children are roughly 90 percent of men's hourly wages, the comparable figure for women with children is 70 percent.
When hourly wages of new employees are compared, the gender gap is very narrow. But by the age when most women begin having children, the birth of these kids penalizes women by roughly 20 percent. Among mothers, those who have more than one child, or who are black, or single, pay an even larger family penalty than married white women with only one child.
This mommy gap has come to light through new, sophisticated research on the gender gap, including the work of Jane Waldfogel at Columbia University.
The very first bill that President Obama signed into law dealt with equal pay for women, but activists say it's done little to close the ongoing difference between what men and women earn.
The law -- the Lilly Ledbetter Fair Pay Restoration Act -- may have extended the amount of time victims have to file discrimination cases, but it hasn't changed this fact: Women, on average, earn only 77 cents to a man's dollar, and the disparity is greater for women of color.
New legislation in Congress aims to close the pay equity gap, even as administration officials prepare to step up enforcement of the existing law.
 - The New York Times front page headline recently tells us that "For Young Earners in Big City, Gap Shifts in Women's Favor." The big surprise? New York City women between 21 and 30 working full-time made 117% of men's wages. Everyone is wondering why. Here's why, for starters...
When I did the research for Why Men Earn More in 2005, I discovered that nationwide never-married women who had never had children earned 117% of the wages of never married men who had never had children. Manhattan women in their twenties are less likely to have married or had children than women in their twenties who live in suburban and rural areas. The overall pay gap with men earning more is not about discrimination; it is mostly about the division of labor once children arrive. - from here
 - a report titled Women's Earnings in 2008, published by the US Labor Department in July 2009, found that in aggregate (without controlling for preferences for higher or lower earning fields), women who have never married earn 94.2 percent of their unmarried male counterparts' earnings a figure that is within less than 6% of wage parity despite the fact that, "women, still..are more likely to choose jobs in education and healthcare, where earnings will tend to be lower." - from here
 - For childless women, the gap is 10 cents on the dollar.- from here
 - Bonus info - In their book “Women’s Figures” (1999), economist Diana Furchtgott-Roth and Christine Stolba meticulously compared data on the earnings of childless men and women aged 27 to 33. They found that the wage gap shrank to 98 cents.