In her blog in The Washington Post, Jena McGregor talks about leadership in the changing world and the role women play in it.

A new Government Accountability Office report just published, finds that female managers earned just 81 cents for every dollar earned by their male counterparts in 2007, compared to 79 cents in 2000.

Women make up just 40 percent of this country’s managerial ranks, and little has changed from the 39 percent ratio in 2000.

Working mothers with children under the age of 18 account for an astonishingly low 14 percent of all managers, a number that hasn’t changed since 2000.

Why does this pay gap still exist?

• It’s discrimination, women groups say.
• It’s education, others say.
• Women don’t negotiate well for raises, other experts say.
• Women are not tough enough to reach the highest level of corporate power, yet another expert says.

The GAO report does not make an effort to explain or analyze its findings, which largely reveal that little has changed. But it does, for the first time, take an in-depth look at the impact of motherhood on the pay discrepancies of male and female managers, which offers revealing clues for the primary reason this perennial leadership issue remains.

Discrimination does play a role and it’s one that should not be discounted. Years of diversity training and equal opportunity policies have done very little to help. But it doesn’t explain the whole problem.

Education can’t be an excuse anymore. Last year women earned more PhD’s than men. For every two men graduating from college, three women do. The GAO found similar improvements: among women aged 25 to 64 in the labor force, the proportion with a college degree roughly tripled from 1970 to 2008.

Women don’t negotiate well? It’s true that few women have reached the highest levels of corporate power: the numbers become far grimmer when you examine just the executive ranks of managers. In 2009, just 13.5 percent of executive officers in corporations were women. That same year, only 6.3 percent of the top earners in business were women. And an amazingly low 2.6 percent of CEOs among the country’s 500 largest corporations are women. In raw numbers, that means just 13 women have reached this high echelon of corporate power.

Aren’t women tough enough? They are, but the main reason, in Jena’s opinion, lies instead in the extraordinary demands on executives’ time, or even on senior managers’ time which are not compatible with raising a family. In a corporate world that demands 24/7 hours and far-flung globetrotting, many women–and increasingly, men–decide the sacrifice is not worth it.

Working-mother managers make just 79 cents on the dollar, compared to their male peers, lower than the 82 cents that non-mother female managers receive. Recent studies have shown that– thanks largely to education gains–young, single, childless women actually out-earn their male peers by a median 8 percent. After that point, female managers with children are simply more likely than men to scale back their hours or be the ones who have to miss the important client dinner, all of which can result in fewer promotions and lesser pay.

Image thanks to http://www.flickr.com/photos/24328644@N08/2509527996/