The web site of the Association of Fundraising Professionals reports the following: "Unmarried women contribute more to charity on average in every income category as compared to unmarried men, according to the Center on Wealth and Philanthropy at Boston College University."
While households headed by unmarried men gave an equal amount to charity as households headed by unmarried women, "female-headed households earned just 71 percent of the income and owned only 55 percent of the net worth of male-headed households. Controlling for income, unmarried women gave slightly more than unmarried men at lower income levels, with the disparity growing wider as income levels rose." For example, in households earning more than $200,000, unmarried men donated an average of $6,526, and unmarried women donated an average of $28,171.
This should tell fundraisers something about where they should concentrate their efforts! Particularly because "there were 31 million households headed by unmarried women in the U.S. in 2004, compared to just 17 million households headed by unmarried men. On aggregate, giving by unmarried females exceeded $23 billion while giving by unmarried males reached just $12 billion."