While some women have risen to the top of U.S. executive boardrooms in recent years – and have made substantial gains in the overall white-collar workforce – females still remain vastly under-represented among the highest ranks of business titans.

“There has been a significant increase in the number of women assuming leadership positions in the U.S. in the past 40 years,” said Anna N. Danielova, assistant professor of finance, DeGroote School of Business in Hamilton, Ont.

Danielova indicated that the percentage of management who were female in U.S. corporations climbed from 18 percent in 1972 to 45 percent in 2000, citing data from the U.S Bureau of Labor Statistics.

“Despite that number, the distribution of women in senior management and executive positions is still severely skewed in favor of men,” she said. “There has been some increase in past 10 years, but women in leadership positions are still statistically under-represented.”

According to Atul Gupta, professor of finance at Bentley University in Waltham, Mass., only twelve of the companies in the S&P 500 index currently have women chief executives, down from 15 in 2010.

Moreover, only 15.7 percent of board-members of corporations in the Fortune 500 are female.

In fact, women may actually be going backwards.

“Progress has slowed dramatically and in some areas [has] declined,” Gupta said.

Certain industries seem to favor women executives more than others.

“We find women on boards in every sector, demonstrating there are women available,” Gupta said.

“However, manufacturing, financial services and technology have lagged other sectors in appointing women since we started tracking in 2003. Interestingly, within the technology sector, women are doing well in software and within life sciences. Women are also doing well in pharmaceuticals and biotech, in contrast to medical devices.”

Indeed, Gupta notes, more than 10 percent of companies in the Fortune 500 have no women board-members whatsoever.

Moreover, 41 percent of the largest 100 companies have no women directors.

Intimately connected to this under-representation of top female executives is a gap in compensation between the genders.

One recent study exhibited a narrowing of the uncorrected gender pay gap from the mid-1990s, Danielova said.

“But after controlling for differences in company size, occupational title, and industry, women top executives earn between 8 percent to 25 percent less than male executives,” she noted.

“The magnitude of the gender pay gap is statistically related to the gender of the chief executive and corporate board chair. Women CEOs and board chairs bring in more top women and at higher pay than is found in non-woman-led firms. Female executives in women-led firms earn between 10-20 percent more than comparable executive women in male-led firms and are between 3-18 percent more likely to be among the highest five paid executives in these firms as well.”

The picture is much brighter across the Atlantic.

Gupta indicates that companies in parts of Europe, particularly Scandinavia, are doing much better in this respect than the U.S.

Citing data from Catalyst.org, almost 40 percent of corporate board seats in Norwegian companies are occupied by women -- making it the world’s most progressive nation with respect to women executives.

The United States is fifth on that list (at 15.7 percent), behind even South Africa.

However, the situation in Britain is also fairly grim for women executives. According to reports, just under 14 percent of companies in the FTSE-100 index have women in their boardrooms.

A recent study by Lord Davies, the former Chairman of Standard Chartered plc, recommended that number be raised to a minimum of 25 percent by 2015.

Some of the most prominent women bosses of public U.S. companies include Patricia Woertz of farm equipment-maker Archer Daniels Midland Company (NYSE: ADM): Andrea Jung of personal care products maker Avon Products Inc. (NYSE: AVP); Laura Sen of discount store retailer BJ's Wholesale Club Inc. (NYSE: BJ); Ellen J. Kullman of chemical giant E.I. DuPont de Nemours & Co. (NYSE: DD); Indra Nooyi of Pepsico Inc. (NYSE: PEP); and Carol Bartz of Yahoo! Inc. (Nasdaq: YHOO).

Looking ahead, the number of women chief executives and board-members is bound to increase – if only because women are outnumbering men in colleges in both the U.S. and U.K.

In some American universities, for example, the ratio between female and male students stands at an astonishing two-to-one.