Kelly Vielmo and partner Jack Montgomery take children (L-R) Ravyn, 2, Raine, 3 and Cardel, 6 to a nearby D.C. restaurant for kid’s night. (Photo by Linda Davidson / The Washington Post)

Planners in D.C. and other cities have had much success luring young professionals to urban neighborhoods, so much so that a prominent question among economists and housing analysts is whether all the millennials who moved to cities will stay once they have children.

Previous generations mostly moved to the suburbs, and there is evidence that many millennials also want to live in suburban single-family homes, even if they live in cities right now. Picket fence and all.

In D.C., as the population grew in recent years the percentage of children dropped. In 1980, 22 percent of District residents were children. By 2010 it was 17 percent.

But in urban planning circles, there is a burgeoning movement to figure out how to better accommodate young families before they depart.

The issue was the subject of a panel discussion in Washington last week in Washington hosted by the Urban Land Institute, an industry group, featuring architectural and former Seattle planning commissioner Sarah Snider Komppa.

Komppa grew up being driven around in the suburbs, which she found somewhat unfulfilling. “You’re shuttled from one place where everyone is the same as you to another place where everyone is the same as you,” she said.

That experience has become something of a norm. In 1970, 60 percent of American school children biked or walked to work, she said. By 2000, it was only 13 percent, and Komppa said there is research showing that added time in the car contributes to higher rates of obesity and lower rates of civic activities like volunteering.

So Komppa recently spent a year traveling to cities in the United States and Canada looking for answers to the question: What happens when millennials grow up and have kids?

One thing she found is many new parents in cities — particularly those in the middle class — going all out to make their urban neighborhoods work for them, by getting new schools opened, building playgrounds, starting family-friendly businesses and pushing for housing choices that provide more space and communal areas where kids can play.

“There will always be sufficient housing for families in the United States. Always. That will never be a question. But there aren’t necessarily the same options in cities,” she said.

Courtesy ULI

Housing — and the numbers of small or micro-units being added in major cities — was a recurring concern. Singles or couples with solid incomes and no children have been such a boon to urban areas that it’s been suggested that tailoring a city’s housing stock for families might not make economic sense.

But another panelist, Mildred E. Warner, a professor at the Cornell University College of Architecture, warned of the consequences: “If you build a city filled with efficiencies and one-bedrooms you are pushing people out at exactly the time that they are starting to put down roots and spend money.”

Like other booming cities, the District’s recent population gains have come largely from white collar renters snapping up new apartments. A good example is Rhode Island Row, a 274-unit project completed in 2011 beside a Red Line Metro station in Northeast.

The developer of the project, Victoria Davis, president of Urban Atlantic, was also on the panel and shared a breakdown of the ages of residents in the building. Of the more than 400 residents there, only five are children:

Davis said she expects more local families to be in the market for apartments in coming years and has begun thinking about how to accommodate them, with larger units featuring bigger closets and smaller kitchens.

She said in another of the company’s buildings, families had begun to store toddlers’ tricycles alongside adult bicycles in a common storage area.

Some argue all this planning, placemaking and housing talk is just bells and whistles, and that the real factors that will prompt parents to decide where to live are the same as they have long been: schools and crime.

Gerald L. Gordon, longtime head of economic development for Fairfax County — who has lured more than his share of companies and families from D.C. — has long held that his greatest weapon in battling for businesses is the county’s top-notch school system.

That sentiment is also reflected in the efforts of Prince George’s County Executive Rushern L. Baker III, who has been heavily focused on economic development and recently proposed a tax increase to improve the county’s school system.

“Let’s face it, the most sought-after counties in this region, this state and this nation are the ones that are safe and have the best public education systems,” Baker said in making his proposal.

Komppa acknowledged that for all the efforts to provide places to play and different transportation options, that for most middle class families: “It’s the schools that are going to make them leave.”

Davis, the developer, also emphasized the importance of schools to communities. But she didn’t know which school the children in her building, Rhode Island Row, were assigned. Perhaps for future projects she will need to.

Follow Jonathan O’Connell on Twitter: @oconnellpostbiz