11/18/2010 04:16 pm ET Updated May 25, 2011

Women CEOs in the Fortune 500 -- A Single Step Forward, Four Steps Back

My book, The Last Male Bastion - Gender and the CEO Suite at America's Public Companies (Routledge 2010), appeared just last March. The book featured profiles of the 21 women who actually have reached the corner officer at large U.S. public companies, including references to the 22nd (Ursula Burns at Xerox). Ms. Burns took office after the manuscript had gone to print.

There have been several twists and turns since that time, with the overall effect being a distinct setback. The total number of women CEOs has fallen, from 15, or 3% of the Fortune 500, which represented the high point, to 12, then in September back up to 13, then most recently back to 12, or 2.4%, where it now rests.

When in 2009 Ursula Burns took office it was a historic moment, not because the number of women in office had reached a new high. It hadn't: Burns replaced another woman, Anne Mulcahy, who had been Xerox's CEO since 2002. The female CEO number stayed at 15. What was historic was that Ms. Burns became our first African American woman CEO.

Very rapidly, though, three women CEOs resigned their positions. Mary Sammons, CEO of Rite Aid, Camp Hill, Pennsylvania, resigned, perhaps be she was tired. Once a high flier in the 1990s stock market, Rite Aid has fallen further and further behind the industry leaders, CVS and Walgreens. For a time the stock has flirted with a price under $1.00, which could mean delisting from the New York Stock Exchange. Sammons and her team seemed never able to pull the company out of its tail spin.

Christina Gold, CEO of Western Union, re-located to outside Denver, stepped down later this spring. She simply retired.

Then, in early summer came word that Brenda Barnes, CEO of Sara Lee, Downer's Grove, Illinois, herself a widely publicized corporate CEO, had a severe stroke in her mid-50s. In June she took a leave of absence, followed in August by her resignation. Kohlberg Kravis & Roberts (KKR), the buyout firm has expressed interest in acquiring Sara Lee and taking the company private but, initially at least, Sara Lee's management rejected the overtures.

So, quite rapidly, the number of women CEOs had dropped from 15 to 12. The number rebounded slightly in late September when Campbell's Soup, of Camden, New Jersey, announced the selection of Denise Morrison as CEO, succeeding Douglas R. Conant.

Ms. Morrison is a food industry veteran, who rose through jobs at Proctor & Gamble, Pepsico, Nestle S.A., Nabisco, and Kraft Foods, before joining Campbell's. She also evidences a common pattern of women who have made it to the top. They side stepped from one company to another, often several times in their careers, before they reached senior management. Only Anne Mulcahy at Xerox and Susan Ivey at Reynolds America are female CEOs who spent most all of their careers with a single company.

The number of women on corporate boards of directors in the U.S. has been basically flat for 5 years now, according to Catalyst, the leading women's advocacy organization. Catalyst, too, inflates the number, counting the number of directorships which are held by women as the number of female directors. The latter number is significantly less, as numbers of women, many of them prominent, allow themselves to be token, or corporate governance ornaments, serving on 4, 5, 6 or 7 corporate boards. The number of women trophy directors has rapidly increased as of late whereas the species has all but disappeared among men.

Then, most recently, in late October, 2010, Susan Ivey at Reynolds America announced her retirement from the CEO position. Her stepping down is quite confounding, as she is only 51 and her leadership at RAI has been unparalleled. She led the company into smokeless tobacco, where future growth will be. She resurrected defunct premium brands, marketing them with premium panache but non-premium prices. The stock's price hovers near an all-time high and the dividends are robust, to say the least.

So, in the immediate year almost past, we have had one new appointment (Morrison) and four resignations (Sammons, Gold, Barnes and Ivey); one step forward, four steps back.