California has more high-profile women political leaders than ever before: U.S. Sens. Barbara Boxer and Dianne Feinstein, and House Speaker Nancy Pelosi in Washington, and here at home, state Assembly Speaker Karen Bass.

Their achievements, individually and collectively, are cause for celebration. But I have to ask: What will it take for us to see similar progress in California's boardrooms and executive suites?

The UC Davis Graduate School of Management, in partnership with the Palo Alto-based Forum for Women Entrepreneurs and Executives, conducts an annual study of corporate gender diversity statewide. Our 2008 census, released this morning, suggests that a woman today stands a better shot at winning a seat in the U.S. Senate than a top CEO job in California.

Only 13 of the 400 largest public companies headquartered in California – 3 percent — have a female CEO today. In contrast, 16 percent of U.S. senators are women.

The picture isn't much better when you step out of the CEO suite. Our 2008 study reveals that 194 of the largest firms based in California – including Intel, Big 5 Sporting Goods and Del Monte Foods – have all-male executive teams.

In addition, 187 firms – including California Pizza Kitchen, Netflix and Grubb & Ellis — have men-only boards of directors.

And at 117 companies – among them Hansen Natural, Sharper Image and McAfee – men occupy not just every one of the top executive offices but every one of the board seats as well.

The last time Congress was an all-boys' club, it was 1920.

What will it take to budge these companies into the new century? Research, like ours, may help. A 2007 study by the advocacy organization Catalyst, for example, found that the Fortune 500 companies with the highest representation of women on their boards experience better returns on equity, sales and invested capital than those with the lowest. Numerous other studies have also found a correlation between the presence of women in corporate leadership and higher shareholder returns, company revenues and profits, and firm value.

Gender diversity was also associated with lower volatility. In our current economic crisis, no company can afford to ignore such findings.

The 2008 elections are over, but we consumers can continue to vote. As consumers and shareholders, we can effect change through our buying habits and proxy power.

As shareholders, we can also effect change through our proxy power. If you are dissatisfied with the gender makeup of the leadership at a particular company (information for the 400 largest companies headquartered in California is available at www.gsm.ucdavis.edu/census), there are relatively easy ways to make your displeasure known.

The Interorganization Network, based in Fort Washington, Pa., lays out several suggestions at www.ionwomen.org. Potential tactics include casting "no" proxy votes on all male board nominees, voting "yes" only for qualified women or simply scribbling "Where are the women?" on proxy statements.

Other options include writing a letter to the chair of the board (examples can be downloaded from the ION Web site), attending an annual shareholders meeting to ask why there aren't more women on the board, or nominating one or more women directors for the next slate of board candidates, following the procedures set out in the proxy statement. Additional ideas are available at www.fweande.org .

Many were disappointed at Hillary Clinton's loss of the Democratic presidential nomination. Overall, women remain underrepresented in political office. But we know that voting works. A record 91 women are serving in the 100th Congress. Women now make up 27 percent of California's 120-member Legislature. It's time that we vote for more women leaders in the corporate sector, too. It's not just a women's issue. It's a good corporate governance issue.

Nicole Woolsey Biggart is dean of the Graduate School of Management at UC Davis.