A new trend in stepfamilies shows more and more couples are living together before marriage.

Susan Stewart, assistant professor in sociology, wrote a book, “Brave New Stepfamilies: Diverse Paths Toward Stepfamily Living,” which looks into the recent trends in the modern American stepfamily.

“Probably the most important trend that is attracting the attention of family researchers is the effect of cohabitation,” Stewart said. “More than 50 percent of families live together before marriage.”

Stewart defined cohabitation as an opposite-sex couple who is romantically and sexually involved and residing in the same household.

Megan Farmer, graduate student in sociology, said a third of all children are born outside of marriage.

“The majority of people will cohabitate at some point in their life,” she said. “With the prevalence of cohabitation, the definition of a stepfamily has changed.”

Farmer said the number of married stepfamilies has decreased a little because of cohabitation.

“You don’t have to be married to be part of a stepfamily,” she said. “It really is an important topic given the current state of our society.”

Cohabitation is also common among people over the age of 65, Stewart said.

Stewart has been doing research on stepfamilies for five to eight years.

She has studied the perceptions of family membership among stepfamilies. She asked a remarried couple how many children they have, and found that each gave different answers.

For example, if the husband enters the marriage with two children and the wife enters the relationship with three children, instead of answering with five, they each would say the number of children they brought into the marriage.

Stewart has personal experiences with cohabitation and stepfamilies as her own parents divorced when she was 8. Her father moved in with his girlfriend right away and her mother stayed single until just recently.

“My mother remarried last year, [and] she’s in her 60s,” Stewart said. “Now I have a stepfather, which is also a stepfamily, although researchers don’t often study stepfamilies with adult children.”

She said it takes time to develop these new relationships.

“It’s not a matter of becoming an instant family,” she said. “It takes many years for stepfamily relationships to become close and meaningful.”

The book will be used as a textbook for sociology classes and will also be available to researchers and students interested in the topic.

“What I’ve done for students is drawn about both qualitative and quantitative research,” Stewart said. “It contains interviews from members for stepfamilies, for example, quotes from stepmothers about parenting.”

The book will also contain columns, newspaper clippings and cartoons to make it more interesting to students.

Farmer was able to read a few chapters of Stewart’s book before its release.

“I think that her book kind of brings together a lot issues,” Farmer said. “It puts it all together in a concrete matter.”