Buying cigarettes in Massachusetts is slowly becoming harder for young people. Nearly a dozen towns across the state have raised the age for buying tobacco products this past year.

Dr. Jonathan Winicoff of Massachusetts General Hospital has been going town to town and city to city, trying to convince local officials to raise the age for buying cigarettes to 21.

“Almost all tobacco smoking begins under the age of 21," Winicoff said. "It turns out if you make it to the age of 21 never having used tobacco, you have only a 2 percent chance of starting.”

Winicoff says data from Needham, where you now have to be 21 to buy cigarettes, is encouraging. The town raised the age in 2006. Since then, Winicoff says, teen smoking rates have dropped by 50 percent.

Critics of raising the age say that if 18 year-olds can drive, vote, marry and fight in wars, they’re mature enough to make their own health decisions. And retailers worry that the measures could cost jobs.

So far this year, communities including Brookline, Belmont and Sharon have raised the age to 21. Other towns, including Canton, Ashland and Dedham have hiked the age to 19.

The smoking age in most of the country is 18, but some states have made it 19. And New York City raised it to 21 in October.