Associated Press
In this Jan. 30, 2009 file photo, co-chairs of the Bill and Melinda Gates Foundation, USA, Bill Gates, right, and Melinda Gates, sit together prior to an interview at the World Economic Forum in Davos, Switzerland.
As women create and control a growing share of wealth in the country, their influence in philanthropy is more evident.

For most of the Bill & Melinda Gates Foundation's 17-year history, Bill Gates has done the bulk of the talking. But at the organization's headquarters in Seattle, where all the major decisions are made, his office is no bigger, no grander than his wife's.

That's hardly rare in the world of high-end philanthropy: Among nearly 90 percent of high net-worth couples, women are heavily involved in making decisions about charitable giving, according to a study released Monday by the The Center on Philanthropy at Indiana University. Thirty-nine percent of couples reported the woman called the shots, and 48 percent said they made joint decisions.

"As women create and control a growing share of wealth in the country, their influence in philanthropy is more evident," said Claire Costello, national foundation executive at Bank of America Merrill Lynch, which sponsored the study.

Melinda Gates, who has been making more media appearances in recent months, describes the family's giving in terms of "Bill and I." In a recent interview with The Financial Times, she said she and her husband talk philanthropy everywhere from the office to the beach, where they enjoy frequent strolls.

"She's not just smiling and posing for pictures," said Peter Winch, a professor at the Johns Hopkins Bloomberg School of Public Health. "She's a consumer of data and she's tough on people about their answers. It's changing people's ideas of the spouse of the rich person who gave the money, to show they can actually do something extremely important technically."

The increasing power and influence of women in philanthropy may have implications for charitable organizations who have targeted their fundraising messages at men, said Una Osili, director of research for the Center on Philanthropy at Indiana University, in a news release.

"Charities need to better understand the different motivations that drive high net-worth women's philanthropy, their more strategic approach to giving and their desire for a deeper, more collaborative experience with the organizations they support," Osili said.

Women approach giving differently, according to the study. Men are more likely to remain loyal to a charity that they've supported before, while women are more likely to ask questions about what their money accomplished before agreeing to reinvest. Eighty-one percent of women said efficient use of gifts was an important motivation for giving, compared to just 69 percent of men.

Women are also more concerned about being actively involved with an organization and are motivated by opportunities to volunteer. More than 87 percent of high net-worth women report they volunteer. Seventy-eight percent of high net-worth men reported the same.

The Financial Times credits Melinda Gates with softening the image of the Bill & Melinda Gates Foundation and steering money toward the social sciences.

"The couple balance each other out on the public front," author April Dembosky wrote. "While her husband has remained the perpetual geek, focusing on technology developments at the foundation, sometimes in blunt or polarizing terms, (Melinda) Gates has brought a human element to the face of the foundation."

The foundation takes a business-like approach to charity, but Gates said her heart also has a say in her decisions.

"You come home from some of these countries and you see how completely different it is," she said. "Just to have a car that you drive down the street and you turn your seat heater on ... it seems superfluous. Very superfluous."

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