A new study published on Wednesday suggests America's definition of family is changing.
In a telephone survey of more than 800 people, Americans were almost equally divided on the issue of same-sex marriage. Most of the respondents said their definition of family included same-sex couples with children, as well as married gay couples.
The survey found an 11 percent decline in the number of people who only define family as husband and wife - with or without children.
The new book-length study was overseen by Indiana University sociologist Brian Powell.
Beyond the debate over same-sex marriage, how a family is defined affects income tax filings, adoption and foster care practices, employee benefits, inheritance rights and other legal matters.
Even though five states and the District of Columbia now allow same-sex marriages, the federal government doesn't recognize such unions. The Census Bureau definition of "family" remains traditional: "A family is a group of two people or more related by birth, marriage, or adoption and residing together."
"Same-sex marriage is a dangerous social experiment," Glenn Stanton, director of family formation studies for Focus on the Family, told the Associated Press. "A lesbian couple who legally married in Massachusetts - are they family? We would say, 'Absolutely not.'"