There's the Addams family, the first family and the Partridge family. But what really counts as family? It seems that children have a lot to do with it.
Brian Powell, a sociology professor at Indiana University, and his team tackled Americans' evolving definition of family -- and their recognition of unmarried couples, gay and straight, as a family -- in a book-length study, "Counted Out: Same-Sex Relations and Americans' Definitions of Family," and separate 2010 survey. Between 2003 and 2010, his team conducted three surveys involving more than 2,300 people.
The new research was released today.
"What we find is that people are moving away from a traditional definition of family and they're moving towards a modern definition of family," said Powell. "That includes a much greater array of living arrangements. They're including a much broader group of people, broader combination of people as families."
Besides the debate over same-sex marriage, the definition of family affects income tax filings, adoption and foster care practices, employee benefits and other matters.
The Census Bureau's definition of "family" remains traditional: "A family is a group of two people or more (one of whom is the householder) related by birth, marriage, or adoption and residing together."
Indeed, the "modern family" comes in many combinations -- and so do Americans, according to the team's research.
The book's authors identified three clusters of Americans: "exclusionists" who hold onto a more narrow definition of family; "moderates" who are willing to count same-sex couples as family if children are involved; and "inclusionists" who have a very broad definition of family.
In 2010, almost everyone -- 99.8 percent -- agreed that a husband, wife and kids count as a family. Ninety-two percent said that a husband and wife without the kids made a family.
"Children provide this, quote, 'guarantee' that move you to family status," Powell said. "Having children signals something. It signals that there really is a commitment and a sense of responsibility in a family."
For instance, 39.6 percent in 2010 said that an unmarried man and woman living together were a family -- but give that couple some kids and 83 percent say that's a family.
Thirty-three percent said a gay male couple was a family. Sixty-four percent said they became a family when they added children. That number was 54 percent in 2003.
"People right now are really reevaluating their views about same-sex couples," Powell said.
In 2006, just over half of Americans surveyed -- 51 percent -- said pets were part of the family.
Nearly 72 percent said in 2006 that it was better for a married woman to change her name and nearly 50 percent said the name change should be required. Fifty-four percent said it was OK for a man to take his wife's last name.
Sixty percent of Americans in 2010 said that if you considered yourself to be a family, then you were one.
The shifts described in Powell's research pleased Jennifer Chrisler, executive director of the Family Equality Council, an advocacy group for same-sex families.
"People are taking a more expansive view of what a family is," said Chrisler. "But for any family that doesn't fit the 1960s Ozzie-and-Harriet mold, slow and steady doesn't feel fast enough."
So in the end, when it comes to defining "Family Ties" and determining "Family Matters," it's "All in the Family."
The Associated Press contributed to this article.