Seattle Mayor Greg Nickels has suggested that the population of Seattle should be "forced" to grow by 350,000 in order to limit suburban sprawl.

Nickels might be on to something here. At a minimum, his suggestion should spark some much-needed dialogue about the future of our beloved city. This dialogue should focus on what's happening to our families with children.

Seattle is undergoing a dramatic evolution. On the heels of a recent increase in building-height caps, dozens of skyscrapers will soon sprout throughout the downtown area — bringing with them a population explosion. This is good news for the continued revitalization of downtown and adjacent areas.

But what's happening below the glamour of the skyline, down at the neighborhood sidewalk level, is not nearly as positive. And, unfortunately, most Seattleites aren't paying attention.

The values and experiences that hold us together and create a common bond, that build community, are easily overlooked. We avoid these softer issues because we've succumbed to the blinding allure of "moving forward," often with a collective sigh of resignation. Or, worse, we avoid them because it's just so "retro" and politically incorrect to recognize certain powerful attributes that make Seattle a great city, such as families with children, single-family homes with backyards, locally owned businesses, and strong, family-centered neighborhoods.

Consider these facts. In 1960, according to census statistics, children under 18 years of age represented nearly 30 percent of Seattle's half-million residents. By 2005, their numbers had dropped by almost half. In 1960, Seattle Public Schools had nearly 100,000 students. Today, the district has fewer than half that number.

Of America's 100 largest cities, only San Francisco has fewer children under 18 years old per capita than Seattle.

Cities that don't proactively attract families with children find themselves in trouble. And this trouble has a cascading effect that touches us all. Schools suffer as fewer and fewer people are invested in ensuring quality and accountability. Diversity of community — one of Seattle's soul-building strengths — suffers as families with children are forced out to the suburbs.

Sometimes, seemingly innocuous decisions drive families away. For example, along 39th Avenue Northeast in Northeast Seattle, 10 full blocks of single-family residential lots have suddenly become prime targets for four-home clusters. If allowed, this level of population concentration in a section of our city with no sidewalks, no storm drains, and severely limited sewers will transform a low-density, almost rural-feeling neighborhood into a maze of jam-packed houses. Yards — a huge draw for young families — will shrink to almost nothing.

In my own Queen Anne neighborhood, a proposed QFC megastore will eliminate 13 units of desperately needed affordable housing, flood residential streets with hundreds of delivery trucks per week, eradicate up to 25 street parking spaces overnight, and create a myriad of pedestrian-safety problems. There's absolutely nothing family-friendly about this type of big-box development in a residential neighborhood.

Flat-out, maximum-density development poses particular risks to family-centered residential sections of our city. A project here, another there, and one day we suddenly ask, "What happened to our neighborhood?" We're quick to assess environmental impacts; perhaps we need a similar "families with children" impact assessment.

In this context, Mayor Nickels has done us a big favor by putting forward his proposal of hyper-population growth. But such growth may very well further accelerate the suburban migration of families with children, unless we work hard to strengthen family-attractive neighborhoods within the city.

Joel Kotkin, author of "The City: A Global History," warns about this "renewed migration" of families out of our urban centers. Kotkin argues that, by catering to the so-called "creative class" of talented singles, artists and wealthy empty-nesters who tend to congregate in downtown areas, cities have made a serious error in judgment that is causing a growing urban exodus, especially of families with children.

Kotkin's analysis invites a healthy debate. Nickels has issued a similar invitation. Let's hope our civic leaders — and those of us on the sidewalks of our neighborhoods — choose to join in before Seattle is further distorted into a city where only the wealthy and childless live.

Timothy Burgess is co-founder of Merkle|Domain, an advertising agency serving nonprofit organizations. He served 12 years on the Seattle Ethics and Elections Commission, is a former Seattle police detective, and is past chairman of the Queen Anne Community Council. He can be reached at tim.burgess@merkledomain.com.