Call them blended families, bonus families or para-kin. Just don't call them stepfamilies. The term - seared into our consciousness through fairy tales and Disney movies - is falling out of favor, even as the ranks of nontraditional families are expanding.

A new poll estimates that at least four in 10 Americans consider themselves part of a stepfamily, but a growing number reject that label, saying it carries a stigma.

"There's no 'step' in my family," said Samantha Sweeney, a school psychologist who lives on Capitol Hill and feels fortunate to have had two fathers - the one who died when she was 2 and the one who raised Sweeney and her sister after their mother remarried.

Sweeney gained two brothers as part of what she calls her blended family. "When we all are together," she said, "we feel very much like a family."

Many therapists also shun the term, which seems to confer second-class status on a stepparent or stepsibling.

"It causes problems," said Mary Kelly-Williams, a therapist, mother of four and stepmother of one who runs the Web site "We're stuck with the language, but it doesn't resonate with people."

The new terminology hasn't totally displaced the old. But many stepfamilies are groping for new ways to describe themselves at a time when half of first marriages end in divorce and four in 10 babies are born to unmarried women. As a result, children are more likely than ever to grow up around step-relatives.

Yet, 40 years after TV's "The Brady Bunch" became a symbol of the changing U.S. family, so little research has been done on stepfamilies that no one knows exactly how many there are today.

In an analysis of the living arrangements of children in 2004, the Census Bureau reported that 17 percent of all children younger than 18 lived in blended families. About 12 percent had at least one half-sibling, and 2 percent had a stepsibling.

But that likely underrepresents the phenomenon. Although the census estimated that about one in 10 households with children had a stepparent present, it counted only a child's primary residence, not the other parent's new family.

In a nationwide Pew Research Center survey released last week, 42 percent of 2,700 adults polled said they had at least one step-relative. Three in 10 have a step- or half-sibling, 18 percent have a living stepparent, and 13 percent have at least one stepchild.

Stepfamilies are more prevalent among people younger than 30, blacks and people without a college degree, according to the poll, "A Portrait of Stepfamilies."

The Pew survey did not define stepfamily, though it noted that young adults are more likely to have grown up with parents who were divorced, separated or never married. That has led to a broadening of the definition of stepfamilies.

"It used to be that stepfamilies mainly referred to divorced parents who remarried," said Andrew Cherlin, a Johns Hopkins University sociologist who has studied families. "Now, unmarried people who have children from a previous relationship may start a stepfamily without either partner having been married."

Regardless of how these families describe their relationships, they are altering the perception of family.

Changing perceptions

Hallmark, which has a trends team that studies anthropological and societal changes, has stopped publishing greeting cards using the word "step." A spokeswoman said there are too many varieties of nontraditional families to justify it, though "step" is an option for personalized cards on the company's Web site.

Off the rack, Hallmark offers sentiments that don't label the relationship, such as this one a stepmother could give to her husband's biological son: "I love you just like a son . . . and you can't get more 'family' than that."

Blended families were common a century and more ago, when life expectancy was lower and women often died in childbirth.

"That's where we get all the fairy tales from," said Francesa Adler-Baeder, a professor of family studies at Auburn University in Alabama and former board member of the Stepfamily Association of America.

Think Cinderella, Snow White and Hansel and Gretel. Wicked stepmothers also play indelible characters in Norse mythology, Malay folk tales and Shakespeare. Stepfathers don't escape the stigma. In 2009, filmmakers remade the 1987 movie "The Stepfather," about a serial murderer who killed his first family and then marries a woman with two sons; he ultimately tries to do them in, too.

Terms of endearment

Ken Katz, 52, of Forest Hills recalls struggling with the terms at age 9, when his parents divorced and remarried. He said he did not feel particularly close to the man who married his mother and thought of him as a stepfather. But he didn't feel comfortable calling the woman who married his father a stepmother because they were close.

"The prefix 'step' is freighted with negativity," he said. "When I was young, I didn't consciously understand why I felt that discomfort. But I'm sure now that when I'd use the phrase, I'd experience the Cinderella notion that the 'step' is always evil. It didn't work to use it, because I felt I was hurting my stepmother."

Now, Katz said, the only time he uses the term for either of his stepparents or stepbrothers is for the sake of clarity when talking to people who have only met one of the two families.

In the Pew poll, seven in 10 pronounced themselves satisfied with their stepfamily life. But a majority said they feel a stronger obligation to help relatives they are biologically related to than they do step-kin.

In fact, stepfamilies can take years to form the emotional bonds taken for granted in other nuclear families.

"When two people fall in love and get married, you can't assume the kids will love each other, too," said Paula Bisacre, a Howard County resident who married a widower eight years ago, forming a blended family with five children.

Her stepchildren refer to her by her first name, as her children do with her husband. Experiences led her to found a magazine, reMarriage, now a Web site for stepfamilies called

"At the end of the day, if everyone in a stepfamily is respectful of each other and caring, that's true success," she said.

Some therapists argue the language can be a hurdle, and even some of the euphemisms for stepfamily are under attack.

"A lot of experts feel the term 'blended family' gives people the false hope that his and her kids can mix together and everything will be one new formation" said Brenda Ockun, who began publishing StepMom magazine after she became one.

More commonly, she said, "people come together with their own traditions and history, and in trying to define the new stepfamily, they struggle to determine what it's supposed to look like. Calling them a blended family can create pressure to instantly bond and look like the first family."

The struggle can last for years, said Tracy Cacho of Upper Marlboro. Her six stepchildren have used various terms to describe her since she met and married their father, a widower. She said she sees her role not as their mother, or as a friend, but as an adult around to support them.

The nomenclature varies with the situation. The children, now 9 to 19, sometimes introduce her to friends as their mom, she said. Alone in the house, they usually call her Tracy. And when she disciplines them, they call her their stepmother, a word that she says confers on her a status one rung lower than "mom."

Whenever Cacho calls their teacher or doctor's office, however, she says she's calling on behalf of her kids.

"I'm okay with the term stepmother," said Cacho, who often blogs on her stepfamily experience. "That's what I am. In the beginning, it hurt. I play the role of mom. But that's how they define me, as their stepmother. Being in a stepfamily, you have to pick and choose your own battles. At the end of the day, I'm a stepmother."