San Francisco has the lowest percentage of kids of any major U.S. city. 13% under 18 vs 21% in NY and 23% in Chicago.
This was particularly eye opening: “For every 100 apartments in the city sold at market rates, the San Francisco school district expects to enroll only one additional student, the report said.”
All of these trends are temporary. Once the current residents die, either new singles move in, or maybe families if the city makes policy choices that are friendly.
The most important reason that I've heard of is that SF won't let you choose a school close to your neighborhood, so you can end up with kids in multiple schools across town, or in schools you don't like.
This was particularly eye opening: “For every 100 apartments in the city sold at market rates, the San Francisco school district expects to enroll only one additional student, the report said.”
https://www.nytimes.com/2017/01/21/us/san-francisco-children...