It's not your imagination that there aren't too many women on corporate boards of directors. I recently did a quick check of a few major companies' boards and found this information:

  • The Procter & Gamble (NYSE:PG) board seems to have 16 seats, with two filled by women -- one of whom is eBay's CEO, Meg Whitman. (13%)
  • Merck's (NYSE:MRK) board seats 12 and features three women. (25%)
  • Avon's (NYSE:AVP) board has 11 people, five of whom are women. (45%)
  • Raytheon's (NYSE:RTN) board seats 12, with two women. (17%)
  • PepsiCo's (NYSE:PEP) board of 14 features four women. (29%)
  • Home Depot's (NYSE:HD) board has 11 people, one of whom is a woman. Lowe's (NYSE:LOW) has the same. (9%)

But that sample is far from scientific, isn't it? Let's turn instead to a recent report from the InterOrganization Network, a group of seven organizations of female executives. It noted the same dearth of women and offered an explanation: "The key to getting more women on corporate boards is getting more women on board-nominating committees."

In ThePhiladelphia Inquirer, Jane von Bergen covered the report and cited a quotation by Princeton University's first female president, Shirley Tilghman, who said, "The world works on lists. . If a woman is involved in constructing those lists, the likelihood of selecting really terrific women goes way up."

Indeed, the InterOrganization Network examined the boards of 536 companies in five regions of the country and found that only about one in four companies had women on their nominating committees.

Does this matter? Well, obviously it matters to many people -- especially to those of us with two X chromosomes. But perhaps it should matter to all investors, too. As I noted in a previous article reviewing another report, having more women in upper management seems to boost companies' bottom lines: "The group of companies with the highest representation of women on their senior management teams had a 35% higher [return on equity] and a 34% higher [total return to shareholders] than companies with the lowest women's representation."

One takeaway for us investors is that maybe, when we evaluate a company as a possible investment, we might want to look at more than its growth prospects, its financial health, and its competitive position. Maybe we should check out the makeup of its upper ranks, too.

Home Depot is a Motley Fool Inside Value pick. Merck is a Motley Fool Income Investor pick. eBay is a Motley Fool Stock Advisor pick. Take the newsletter(s) that best fits your investing style for a 30-day free spin.

Longtime Fool contributor Selena Maranjian owns shares of Home Depot and PepsiCo. The Fool has an ironclad disclosure policy.