Our recent story about the increasing trend of families leaving the city once their kids hit school age garnered a lot of attention inside and outside City Hall. As we noted, despite years of policy initiatives by city and school officials, new census figures show 5,278 fewer kids living in the city in 2010 than in 2000. That means just 13.4 percent of San Francisco residents are kids - one of the lowest percentages of any city in the country. Is it just a given that not many kids will grow up in the city, or can more be done?