A new study that finds children of a gay or lesbian parent may be more likely to have social and emotional problems has sparked controversy on both sides of the same-sex marriage debate.

The study, from Mark Regnerus, an associate professor of sociology at The University of Texas at Austin, surveyed more than 15,000 Americans between the ages of 18 and 39, asking them questions about their upbringings. Its findings are published in the July issue of Social Science Research.

One survey question asked whether a parent had been in a same-sex relationship during a child's upbringing; Regnerus wanted to see whether there were differences between kids raised in a household by a parent in a same-sex relationship compared with those who were raised by biological parents who were married and heterosexual.

Sixty-nine percent of children of lesbian mothers reported that their family received public assistance, such as welfare at some point, compared with 17 percent from intact biological families. About half of children of an intact biological family said they were employed full-time, compared with 26 percent of those born to a lesbian mother. Fourteen percent of kids of a lesbian mom spent time in foster care at some point, compared with 2 percent of the rest of the children studied. Overall, less than 2 percent of all respondents who said their mother had a same-sex relationship reported living with their mom and her partner for all 18 years of their childhood.