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The fact that the average American working woman earns only about 8o% of what the average American working man earns has been something of a festering sore for at least half the population for several decades. And despite many programs and analyses and hand-wringing and badges and even some legislation, the figure hasn't budged much in the past five years.

But now there's evidence that the ship may finally be turning around: according to a new analysis of 2,000 communities by a market research company, in 147 out of 150 of the biggest cities in the U.S., the median full-time salaries of young women are 8% higher than those of the guys in their peer group. In two cities, Atlanta and Memphis, those women are making about 20% more. This squares with earlier research from Queens College, New York, that had suggested that this was happening in major metropolises. But the new study suggests that the gap is bigger than previously thought, with young women in New York City, Los Angeles and San Diego making 17%, 12% and 15% more than their male peers, respectively. And it also holds true even in reasonably small areas like the Raleigh-Durham region and Charlotte in North Carolina (both 14% more), and Jacksonville, Fla. (6%). (See TIME's special report on the state of the American woman.)

Here's the slightly deflating caveat: this reverse gender gap, as it's known, applies only to unmarried, childless women under 30 who live in cities. The rest of working women  even those of the same age, but who are married or don't live in a major metropolitan area  are still on the less scenic side of the wage divide.

The figures come from James Chung of Reach Advisors, who has spent more than a year analyzing data from the Census Bureau's American Community Survey. He attributes the earnings reversal overwhelmingly to one factor: education. For every two guys who graduate from college or get a higher degree, three women do. This is almost the exact opposite of the graduation ratio that existed when the baby boomers entered college. Studies have consistently shown that a college degree pays off in much higher wages over a lifetime, and even in many cases for entry-level positions. "These women haven't just caught up with the guys," says Chung. "In many cities, they're clocking them."

Chung also claims that, as far as women's pay is concerned, not all cities are created equal. Having pulled data on 2,000 communities and cross-referenced the demographic information with the wage-gap figures, he found that the cities where women earned more than men had at least one of three characteristics. Some, like New York City or Los Angeles, had primary local industries that were knowledge-based. Others were manufacturing towns whose industries had shrunk, especially smaller ones like Erie, Pa., or Terre Haute, Ind. Still others, like Miami or Monroe, La., had a majority minority population. (Hispanic and black women are twice as likely to graduate from college as their male peers.) (See the top 10 female leaders.)

Significantly, the conditions that are feeding the rise in female wages  a growing knowledge-based economy, the decline of a manufacturing base and an increasing minority population  are dominant trends throughout the U.S. "This generation [of women] has adapted to the fundamental restructuring of the American economy better than their older predecessors or male peers," says Chung. While the economic advantage of women sometimes evaporates as they age and have families, Chung believes that women now may have enough leverage that their financial gains may not be completely erased as they get older.

The holdout cities  those where the earnings of single, college-educated young women still lag men's  tended to be built around industries that are heavily male-dominated, such as software development or military-technology contracting. In other words, Silicon Valley could also be called Gender Gap Gully.

As for the somewhat depressing caveat that the findings held true only for women who were childless and single: it's not their marital status that puts the squeeze on their income. Rather, highly educated women tend to marry and have children later. Thus the women who earn the most in their 20s are usually single and childless.

The rise of female economic power is by no means limited to the U.S., nor necessarily to the young. Late last year, the Bureau of Labor Statistics announced that for the first time, women made up the majority of the workforce in highly paid managerial positions. The change in the status quo has been marked enough that several erstwhile women's advocates have started to voice concerns about how to get more men to go to college. Is there an equivalent to Title IX for men?

See poll results on men, women and society.