Over the last few decades, women have made great strides toward gender equality in many arenas -- but not on corporate boards.

A recent article in The Atlantic, penned by a researcher from GovernanceMetrics International, has shone a fresh spotlight on this long-standing problem. Women hold only 12% of board seats at major U.S. companies. In a pool of 4,000 of the world's largest corporate entities, 40% lacked even one woman on their boards. Of those 4,000 companies, just one lonely company boasted a board with a female majority.

The Atlantic focused on 23 companies that have exactly zero women on their boards. Here's a sample of the more surprising examples:

  • IAC Interactive (Nasdaq: IACI), parent of Match.com, made the list. Perhaps somebody should match it up with some female directors.
  • Baltimore, Md.'s Under Armour (NYSE: UA) recently cheered about its efforts to add more female athletes to its customer base, even predicting that one day, women's apparel will overshadow its male apparel business. Unfortunately, it hasn't quite translated that business interest into a similar interest in including women on its board.
  • Skechers (NYSE: SKX) has made big money from female consumers through female-focused trends like its Shape-Ups line, but it hasn't shaped up its boardroom with a dose of gender diversity.
  • Crocs (Nasdaq: CROX) has admitted that its kids and women's markets are the strongest part of its business. Apparently, strengthening its board by appointing female directors simply wasn't part of that agenda.
  • One of my personal favorite stocks, Urban Outfitters (Nasdaq: URBN), has no women on its board, despite its major female clientele. Heck, almost three-quarters of major retail companies have at least one female director. Get with the program, dudes.
  • Diamonds may be a gal's best friend, but diamond jewelry purveyor Zale (NYSE: ZLC) is not, at least with regard to the folks in its boardroom.

Underutilized assets
As the Atlantic piece points out, the progress women have made in many other areas makes this discrepancy even stranger. Girls have been outdoing boys in school, earning higher grade point averages in high school, and outpacing male counterparts in gaining college degrees by a ratio of 3:2.

According to the U.S. Department of Labor's 2009 statistics, women comprise 46.8% of the workforce, by no means a minority figure. The data showed that a not-insignificant 40% of employed women worked in management, professional, and related occupations; that was also the largest percentage concentration in the careers tracked.

Although some women may get lost on their way to the top for a variety of factors, like time off for child-rearing, many women doubtlessly remain overlooked as good candidates for promotions (and ultimately, board seats). Among other explanations for the gender gap, groups generally appoint folks just like them to serve, and most boards -- and their networks -- consist primarily of men.

Many companies clearly lag behind the times -- and given the studies suggesting that women executives yield real performance, they may be missing out. The nonprofit Women Corporate Directors organization last year pointed out that females exhibited a more positive outlook on better corporate governance and risk management policies. To ensure more effective corporate boards, many companies might consider the importance of including more women.

Celebrate differences
Collections of people who think differently often make better decisions than homogenous groups who all think alike. Fuller female participation on boards would provide a much-needed depth of perception and experience that many companies clearly lack. Let's hope The Atlantic can draw much-needed attention to this glaring deficit in corporate America. Seriously, guys, what century is this, anyway?

Check back at Fool.com every Wednesday and Friday for Alyce Lomax's columns on corporate governance.

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Alyce Lomax owns shares of Urban Outfitters; for more on this and other topics, check back at Fool.com, or follow her on Twitter: @AlyceLomax. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.