By Phyllis Korkki for The New York Times – ISN’T it just a matter of time before women reach parity with men in the upper ranks of the corporate world?

After all, women in the United States now collect nearly 60 percent of four-year degrees and they make up nearly half the American work force.

But despite headline-grabbing news like the recent naming of Meg Whitman as chief executive of Hewlett-Packard, a look at the numbers shows that progress at the very top has stalled. Last year, women held about 14 percent of senior executive positions at Fortune 500 companies, according to the nonprofit group Catalyst, which focuses on women in the workplace. That number has barely budged since 2005, after 10 years of slow but steady increases.

So what’s the holdup? Ilene H. Lang, president and chief executive of Catalyst, says one factor can be traced to an “entrenched sexism” that is no less harmful for being largely unconscious.

“I don’t want to blame this on men,” Ms. Lang said. Rather she cites “social norms that are so gendered and so stereotyped that even though we think we’ve gone past them, we really haven’t.”

She describes a corporate environment that offers much more latitude to men and where the bar is much higher for women. In her view, men tend to be promoted based on their promise, whereas women need to prove themselves multiple times.

She maintains that unintentional bias is built into performance review systems. Words like “aggressive” may be used to describe ideal candidates — a label that a man can wear much more comfortably than a woman.

Companies must make a commitment to women’s advancement by holding managers accountable for promoting women and actively measuring their progress, Ms. Lang says, adding that “there’s a big difference between awareness and action.”

Not that there hasn’t been some progress. A rich source of female talent exists just below top management, says Sylvia Ann Hewlett, founding president of theCenter for Work-Life Policy, a research organization. But women have become stuck in this layer because they tend to lack a sponsor at the top to advocate for them, she says.

Sponsors are different from mentors, who lend friendly advice and allow workers to share their quandaries and challenges. Sponsors make a direct bet on the promotion of their protégés, putting their own careers on the line by doing so. That can be risky, so such relationships demand a high level of trust.

”Women tend to be overmentored and undersponsored,” says Ms. Hewlett, who has done research to find out why. One reason is that women are more uncomfortable using their work friendships to land a deal or to join a team, she says. For men, those kinds of interactions tend to be second nature.

Another tripwire is more insidious because it is awkward to discuss. Most of the people in senior management are men, but many are very reluctant to take on women as protégées because of the sexual dynamics, Ms. Hewlett says. They fear that gossip will spread if they are seen regularly with a junior female colleague.

Companies must face this uncomfortable reality head-on, she says. They need to make sponsorship a transparent and integral part of the culture, so that when a male senior executive is seen with a lower-level manager, it will be assumed that he’s a sponsor.

“When women have a sponsor they really do move up,” Ms. Hewlett says, “but you can’t just be a wallflower and wait for someone to pick you.” Actively working to find a sponsor is good practice for a higher leadership position, she adds, because it is all about “leveraging the power relationships in your life.”

SELF-PROMOTION is another crucial skill for those intent on moving up, but women are more likely to consider such behavior unseemly, says Peggy Klaus, an executive coach and leadership expert in Berkeley, Calif. With men, “it’s expected that you’re going to showboat a little,” she says.

Women tend to put their heads down, do great work and praise others in their department while modestly omitting their own contributions, Ms. Klaus says. “Then they get really angry,” she says, “when they get passed over for the bonus and the promotion.”

As Ms. Hewlett put it, “Women have this extraordinary faith in the meritocracy,” and this can carry them through at lower levels. But they need more if they are going to push through to the very top.

To read the New York Times story, click here.