It’s time to get rid of the “Sex and the City” image and start making New York a city where people can have both sex and children. This will become more important as the millennial generation enters its late 20s and early 30s later this decade. This is when many young migrants to the city, including upwardly mobile immigrants, typically become ex–New Yorkers.
Despite all the “back to the city” hype, New York over the past decade suffered one of the highest rates of out-migration of any region in the country. Young singles may come to New York, but many leave as they get older and have families. An analysis by the city controller’s office in 2005 found that people leaving the city were three times more likely to have children than those arriving.
Joel Klotkin, "Why New York City Needs a New Economic Strategy"