Last week Los Angeles passed a law to ban the product where smoking is banned.
"I am most concerned about kids," city lawmaker Paul Koretz, co-sponsor of the ban was quoted as saying by AFP, a news agency.
"We all know this is being marketed to kids, getting some kids who don't smoke tobacco to start.
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Some states, including Italy and France, have already outlawed sales to minors.
A recent study published in JAMA Pediatrics, a journal of the American Medical Association said e-cigarette use is growing among young people.
Just over three percent of US adolescents had ever tried an e-cigarette in 2011, and that more than doubled to 6.5 percent in 2012
Youths who had tried e-cigarettes were more likely to experiment with conventional cigarettes, and were more likely to be current cigarette smokers than kids who had not tried them, said the study.
The US Food and Drug Administration is studying the product to determine whether it should be regulated.
But it ma