The lack of women on corporate boards and in executive suites in the United States is hampering profitability, and investors and investment advisors can do something about it, according to Joe Keefe, President and Chief Executive of Pax World Management and Pax World Funds.

Women currently account for 3% of the CEO roles and 15% of the board positions of Fortune 500 companies. Women also represent 51% of middle managers, but just 15% of senior executive board positions.

For investors, ignoring the lack of women in those positions is like not paying attention to other crucial financial factors such as cash flow and price/earnings ratio, Keefe said at the Women Advisors Forum conference in New York on Thursday.

“When women are at the table, the discussion is richer, the decision making process is better, management is more innovative and collaborative and the organization is stronger,” Keefe said. “It’s not just me saying this, it’s research saying this.”

In 2011, Catalyst released a study that found that from 2004 to 2008, companies with three or more women on their boards outperformed companies with no women on their boards by 84% when it came to return on sales; 60% for return on invested capital; and 46% for return on equity.

A 2008 McKinsey study also found that companies with more women in senior management roles also had above average earnings and financial valuations.

Pax is one firm that has focused on gender as an investment strategy. Its Pax World Global Women’s Equality Fund is the only U.S. mutual fund focusing on investing in companies that promote gender equality globally in their internal policies and programs.

Pax has also adopted a voting policy to reject any company’s annual proxy that does not include any female members on its board of directors, Keefe said. These days, Keefe said the firm even sometimes requires at least two female members on those boards.

Investors and investment advisors can make a difference by screening for companies that promote gender equality, participating as active shareholders and taking part in votes for corporate boards.

Keefe, who is a former Democratic nominee for U.S. Congress in New Hampshire, said the inspiration for gender equality as an investment concept came to him 18 years ago.

It was at that time that he read The Wealth and Poverty of Nations by David S. Landes and also when his daughter was born. Keefe said he was struck by one line in the book that pointed to the role of women as crucial to a nation’s growth and development.

“I remember thinking at the time that this is sort of the key to alleviating poverty globally,” Keefe said. “Gender inequality is the number one impediment to sustainable development around the world.”