"Our responsibility today is to do everything we can to reduce," the number of young people who start smoking, Quinn said.
But a spokesman for the National Association of Convenience Stores suggested the measure would simply drive younger smokers to neighboring communities or corner-store cigarette sellers instead of city stores. Smoker Audrey Silk said people considered old enough to vote and serve in the military should be allowed to decide whether to use cigarettes.
"Intolerance for anyone smoking is the anti-smokers' excuse to reduce adults to the status of children," said Silk, who founded a group that has sued the city over previous tobacco restrictions.
Advocates for the measure say the parallel isn't voting but drinking. They cite laws against selling alcohol to anyone under 21.
With support in the City Council and the backing of Mayor Michael Bloomberg, the measure has the political ingredients to pass. A hearing is set for May 2.
Smoking has become less prevalent overall in New York City over the last decade but has plateaued at 8.5 percent among the city's public high school students since 2007. An estimated 20,000 of them smoke today.
It's already illegal for many of them to buy cigarettes, but raising the minimum age would also bar slightly older friends from buying smokes for them.
The age limit is already 21 in Needham, Mass., and health officials have agreed to the same change but not yet implemented it in another Boston suburb, Canton. A similar proposal is on hold in the Texas Legislature.