Before moving with her boyfriend of three years to a Hampden home this September, Brandy Washington lived with two other women, both young professionals in their 20s, just like her.

Delaying marriage is a lifestyle that has suited the 27-year-old. She and her boyfriend wanted to "try things out" and live together before becoming more serious - a far cry from her high-school-sweetheart parents, who married right out of college. Almost all of her peers, Washington said, are living the same way, either with friends or a long-term partner. They have few serious personal commitments, and are free of social stigmas pressuring them to get married and have children on a specific timeline.

"Living in Baltimore, it's definitely more liberal than other parts of the country," said Washington, who works in marketing. "It's nice to have camaraderie and people who are going through some of the same situations as you are. It's a great way to prolong your youth as well."

New U.S. Census Bureau data indicate that her choice is becoming more common here. Baltimore and Washington are among a handful of U.S. localities where fewer than 10 percent of households are made up of married couples and their children. In the city, 8.6 percent of households are such nuclear families, compared to 23 percent statewide and nationwide.

Young adults like Washington and her friends may be fueling the changes. Since 2000, the census data indicate, Baltimore has seen a jump in the number of people living apart from family. Just over half of all city households consist of families of any kind, a decline of 5 percent since 2000. Meanwhile, an increasing proportion of households consist of people living alone.

"There's a perception that what you do after you graduate isn't [getting] married," said Peter Darrell, 26, who works in commercial real estate and shares a home with his brother and two roommates in Patterson Park. "You go and make yourself into a person, you have an adventure, you do something, and then you go get married."

Though his mother married at 23 and his grandmother married at 18, Darrell said talk of marriage is "just starting to creep" into conversations with his peers.

The low proportion of nuclear families in Baltimore is also influenced by other factors, including the large number of families led by single women. And the trend is happening all across the state, from rural Allegany County to Southern Maryland. In almost every locality, the figures show a smaller share of households are made of nuclear families than a decade ago.

Only in Howard and Calvert counties do more than 30 percent of households fit the married-parents mold, according to the census data released last week.

"The main trend is delay, a sort of delay in committing," said Stefanie DeLuca, a Johns Hopkins University professor who focuses on families and adolescence. "The family structure reflects this protracted transition into adulthood."

Andrew Cherlin, a Hopkins professor who researches changing American family patterns, said the nationwide shifts partly reflect an aging population that includes more married couples whose children have left home, and more older Americans living alone.

Though that may be true in Maryland, where the median age has increased by one year, to 37, the median age in Baltimore is essentially the same as in 2000, at 35.

The restructuring of American households is affecting local school policies, employer benefits packages and hospital visitation policies. It's even making its mark on popular culture, though slowly, said Nsenga Burton, a media scholar who teaches at Goucher College.

Despite the success of sitcoms such as "Modern Family," an ABC show that depicts a sprawling, unconventional American clan, movies, commercials and television shows depicting the "Ozzie and Harriet" style of 1950s family life are still far more common, Burton said.

"The fact that we're still putting forth this image of man, woman, two children and a dog for as long as we have really hasn't been truthful or valid," Burton said.

She praised a recent commercial for Amazon's Kindle that depicted an African-American grandmother giving the e-book reader to her curious and engaged grandson. For some people, that commercial validates the fact that many people have assumed care for grandchildren, and affirms that it's not "the worst possible thing that could happen," Burton said.

About two years ago, the city school board updated its family engagement policy, clarifying its definition of "parents" as "a wide range of adults who take responsibility for supporting the child," said Michael Sarbanes, who directs community engagement for the schools. He said the move came in response to feedback from aunts, grandparents, legal guardians and other adults who care for children.

"We are not assuming a two-parent family model when we talk about engaging families," Sarbanes said. "We're assuming whoever's in that child's support network who's really helping them succeed."

Married parents expressed surprise at census statistics that showed the drop in Baltimore's nuclear families.