Demographer Cassandra Dorius, a postdoctoral fellow at the University of Michigan Institute for Social Research in Ann Arbor, analyzed data on nearly 4,000 U.S. women who were interviewed more than 20 times over a period of 27 years.
The data included information about individual men in each household, describing what demographers call "relationship churning." Dorius found multiple fathers is common -- 28 percent of all U.S. women with two or more children have children by more than one man -- and it is frequently tied to marriage and divorce rather than just single parenthood.
"We tend to think of women with multiple partner fertility as being only poor single women with little education and money, but in fact at some point, most were married and working, and going to school and doing all the things you're supposed to do to live the American Dream," Dorius says in a statement.
However, different fathers was more common among minority women -- 59 percent of African-American mothers, 35 percent of Hispanic mothers and 22 percent of white mothers reported multiple partner fertility.
The study was presented at the annual meeting of the Population Association of America in Washington.