Women, by many accounts, have all the makings to be on top. More than 70 percent of high school valedictorians in 2012 were women. For decades, more female students than male students have graduated from college. Afterwards, more of them than their male counterparts—some 53 versus 47 percent—claim entry-level management jobs, according to a report by McKinsey Research

But somewhere along the line, the numbers drop for women: to 37 percent for mid-managers, and even lower, to 26 percent, for vice presidents and up. Women head slightly more than 4 percent of Fortune 500 companies. Ten years ago, women held 14 percent of these companies’ board seats; today, it’s 17 percent. A slow burn if ever there was one, that’s for sure. While there’s no longer a question of whether a woman can succeed in “a man’s world”—of course she can, and does—these numbers indicate that either the glass ceiling is thicker and lower than we imagined, or that younger women on the way up are finding a way out.

Or, quite possibly, both.

Unreached female potential is not for lack of desire. In her book Necessary Dreams: Ambition in Women’s Changing Lives, Anna Fels writes that starting in childhood both genders have remarkably similar desires for achievement. Both boys and girls dream of accomplishment, recognition, and honor requiring work or skill. They grow up wanting the same things.

“Both boys and girls dream of accomplishment, recognition, and honor requiring work or skill. They grow up wanting the same things.”

Nor is it for lack of confidence. Research, including studies out of Cornell, has long found that women and girls, more than men and boys, tend to underrate their own performance. But that’s changing. A new study conducted by global communications firm Fleishman Hillard and Hearst Magazines, titled Women, Power & Money, found that younger female employees entering the workforce are more likely to perceive themselves as equal to, or better than, men. They see themselves as stronger communicators, and better at recovering from setbacks. 70 percent of Generation Y women in the study described themselves as smart, compared with only 54 percent of men.

We know that there are plenty of obstacles facing women in the workplace: Primitive maternity-leave laws, slow turnover at corporate boards, from which many (men, mostly) don’t retire until the mandatory age of 72. There’s also the fact that although more women are working outside the home, they’re still expected to carry out many of the domestic duties. Although the number of stay-at-home fathers—about 154,000, according to the 2010 Census—is on the rise, women still carry out more of the domestic work, according to a report by Pew Research Center. What’s more, there is an unconscious bias that remains prevalent in many workplaces. After all, women continue to receive less pay for equal work than their male colleagues, and less of other things, too.

Recall the story of transsexual Stanford neuroscientist Ben Barres, who has noted that as a man he is treated with more respect and interrupted less often. Barres recounted how he once overheard a faculty member say, “Ben Barres gave a great seminar today, but then his work is much better than his sister’s.” The “sister,” of course, was when Ben was Barbara. Look, too, at the introduction of “blind” orchestra auditions, in which candidates are evaluated from behind a screen. Since implementation, the percentage of women hired by the top five U.S. orchestras has risen from less than 5 percent to 34 percent. It’s hard to expect more when society tells women, over and over, to expect less.

“Persistent bias felt or perceived at any point in a woman’s career can erode her own ambition by causing her to feel less confident about her skills and abilities.

She then strives for less.”

But what if the biggest obstacle is the one that remains in women’s minds? In her much-discussed book, Lean In, Sheryl Sandberg writes that fewer women than men aspire to senior positions, big paychecks, and high-powered careers. They don’t even try. Could women be imparting this “unconscious bias” on themselves? Could bias, in fact, happen not only from the top down but also the inside out? It can. Persistent bias felt or perceived at any point in a woman’s career can erode her own ambition by causing her to feel less confident about her skills and abilities. She then strives for less. She doesn’t get the promotion or the raise not because it’s given to a man, or because she somehow doesn’t measure up, but because she’s voluntarily taken herself out of the running. It’s not confidence or ability that women are lacking, but ambition they’ve lost—or let go of—along the way.

Ambition relies heavily on a belief in one’s own potential, which means that studies like the Fleishman Hillard one show there’s movement afoot. A generation of women coming to the workforce with a strong sense of their own competence bodes well for continuing high aspirations. The good news is that, as Fels writes, ambition isn’t something that, once extinguished, is gone