Women in the United States age 50 and older collectively control net assets of $19 trillion. They also give more of their income to charity than their male counterparts when other factors are equal.

Those are among the findings of a new study, “Women Give 2012,” conducted by the Women’s Philanthropy Institute, a part of the Center on Philanthropy at Indiana University in Indianapolis, Ind. The findings show that women who are Boomers and older give more even though women generally earn less than men, outlive their male partners and have less money in retirement.

“(Baby) Boomer women are gaining in wealth and education, and they’re going to have an impact on the charitable sector,” said Debra Mesch, Ph.D., director of the Women’s Philanthropy Institute.

The study found that households headed by a single female born before 1965 (Baby Boomers and older) give 89 percent more of their permanent income than households headed by a single male born before 1965. Among the wealthiest 25 percent of that group, female-headed households give 156 percent more than male-headed households.

In the same demographic, 19 percent of female-headed households gave more than 3 percent of their permanent income to charity, compared to 11 percent of male-headed households. Only 24 percent of women gave nothing, less than the 26 percent of men who gave nothing.

Among the wealthiest 25 percent, it was 23 percent of women and 13 percent of men donating 3 percent or more of their income. And, only 3 percent of the wealthiest women, as compared to 8 percent of men, gave nothing. That means that more men gave less of their income (between 0 and 3 percent) than women: 89 percent of men versus 81 percent of women overall, and 87 percent as opposed to 77 percent for the wealthiest 25 percent.

At 76 million, Baby Boomers — those born between 1946 and 1964 — are the largest generation in the United States. Until the year 2030, every day some 10,000 will reach the retirement age of 65. Of the top female wealth-holders, almost half, or 47.2 percent, are between the ages of 50 and 70, which roughly corresponds to Baby Boomer ages.

“Maybe the pie is smaller of what (Boomer women and older) can donate, but they donate a bigger slice of that pie,” Mesch said.

Despite having incentives to give less, Boomer women and older contribute more to charity than men who are Boomers and older. The study identified four factors that might prevent some women from donating. Financial risk aversion, longer life span, being single as they age and retirement all would seem to dissuade older women from giving money to charity; they have less money and must make it last longer than men the same age, but those reasons do not seem to prevent them from contributing to nonprofits.

“Women are socialized to have stronger caretaking motivations than men,” said Mesch, adding that female networks or giving circles increase the giving power of the individuals involved. “The network is really important in giving to charity,” she said.

Women Give 2012 surveyed 1,109 male and female single-headed households whose decision makers were born in 1964 or before. Data is from 2003, 2005 and 2007. It builds upon a prior study done by the Women’s Philanthropy Institute, “Women Give 2010,” which examined the giving of single men and women of all ages. Because married couples tend to pool their resources and collaborate on fiscal decisions, the researchers concluded surveying married couples would not be useful in a study about gender differences in giving.