Census numbers show that San Francisco families are fleeing the city for other bays. Why? Well, for starters, larger houses, roomier backyards, and more affordability. As soon as wee ones leave the stroller stage, it seems, parents decide to ditch the city. And while the younger, more jaded San Franciscan might think that's just swell -- really, who wants to see a stroller at their favorite bar? -- this flight is not good for a thriving metropolis.

The Chronicle reports:

New census figures show that despite an intense focus by city and public school officials to curb family flight, San Francisco last year had 5,278 fewer kids than it did in 2000.

The city actually has 3,000 more children under 5 than it did 10 years ago, but has lost more than 8,000 kids older than 5.

Just 13.4 percent of the city's 805,235 residents are younger than 18, one of the smallest percentages of any city in the country. In 1970, those younger than 18 made up 22 percent of San Francisco. In 1960, they made up 25 percent.

One of San Francisco's most notoriously hypocritical politicians, Gavin Newsom, ditched the city he ran for two terms soon after his wife, Jennifer, pooped out their second child. "I'm not moving out of the city," Newsom told The Chronicle. "It's just a new mother who wants to be close to her family a few miles away. We're temporarily relocating."

In other words, Gavin Newsom moved out of the city. Thanks for leaving the dinner party without helping out with the dishes again, Lieutenant Governor. Sigh.

Anyway, the disparity between hyper-wealthy families and families living well below the poverty level are glaring. The city, it seems, just isn't accommodating to middle class clans.

A few reasons why families are fleeing in record numbers, according to The Chronicle? A new school assignment system "that gives some priority to children living near a school"; the alleged "Manhattanization" of San Francisco, which claims that City Hall is more "geared toward benefiting mostly highly skilled, professional industries"; the astounding ost of private school; and overall cost of living.

Other reasons we think families are leaving? Many new parents, who moved here from more lackadaisical towns, freakout when they have kids and feel the need to move back from which they came; crime; and public displays of gay affection that secretly irk rookie parents.

Why do you think parents are leaving the city?