At City Journal, authors Joel Kotkin and Ali Modarres wonder if the modern city can still be a place for families, or if cities are now only for the childless. They point out that, historically, cities were based on family life, right up until the last century or so. Then, the suburbs happened: folks with children wanted more space, better public schools and cheaper housing. What they lost (access to the arts, culture, more extensive food choices) didn’t seem as important as a yard and three bedrooms. Have cities now e the domain of the childless?

Demographic trends seem to bear out this vision. Over the past two decades, the percentage of families that have children has fallen in most of the country, but nowhere more dramatically than in our largest, densest urban areas. In cities with populations greater than 500,000, the population of children aged 14 and younger actually declined between 2000 and 2010, according to U.S. Census data, with New York, Chicago, Los Angeles, and Detroit experiencing the largest numerical drop. Many urban school districts—such as Chicago, which has 145,000 fewer school-age children than it had a decade ago—have seen enrollments plummet and are busily closing schools. The 14-and-younger population increased in only about one-third of all census-designated places, with the greatest rate of growth occurring in smaller urban areas with fewer than 250,000 residents.

Consider, too, the generation of Americans between the ages of 25 and 34 in 2000. By 2010, the core cities of the country’s 51 most populous metropolitan areas had lost, on average, 15 percent of that cohort, many of whom surely married and started having children during that period. While it’s not possible to determine where they went, note that suburbs saw an average 14 percent gain in that population during the same period.

It’s not that families don’t like the city; it’s often that they can’t afford to live there in the manner that they’d like. One Brooklyn resident, Kari Browne says, “It’s an amazing place. But the key concern is: Can you afford to stay?”

Time Out Chicago asked its readers to make the case for city v. suburbs for families. In a roundtable discussion, parents noted that while suburban public schools were good, they lack diversity. City housing costs were a problem, but those that chose city life loved the easy access to arts and cultural life.

If cities want to stay viable for families (and that means economically viable as well), they’ll need to figure out how to keep and attract families. What will that take? Kotkin and Modarres give two attractions for families: green space and affordable housing.

Families are also deeply attracted to open space. The great Frederick Law Olmsted–designed New York parks, including Prospect Park in Flatbush, are enormous assets for families without backyards. Irvine may lack stunning urban architecture and glorious cathedrals, but it has a magnificent park system that gives residents ideal settings for recreation, exercise, and family gatherings…

What families need is more affordable urban neighborhoods with decent schools, safe streets, adequate parks—and more housing space. As New York University’s Shlomo Angel points out, virtually all major cities worldwide are growing outward more than inward—and ing less dense in the process—because density drives families away from urban cores and toward less dense peripheries. The lesson is clear: if cities want families, they should promote a mixture of density options.

Mildred Warner and Rebecca Baran-Rees of Cornell University point out munities need people of all ages to remain economically viable. In their paper “The Economic Importance of Families With Children”, they point out that families promote economic growth in three critical ways:

Families with children spend the most money in a local economy.Local economies depend on the goods and services (like day care and housing) that families with children require.Families with children mean long-term economic growth for cities.

Cities can be for families, and families are necessary for cities’ economic stability and survival, but like any worthy endeavor, this won’t just “happen”. It will require cities to plan effectively to attract and keep families within city limits, while giving families options that are far-less limited than they are now.