SAN ANTONIO -

For the last several years, electronic cigarettes or "e-cigarettes" have been marketed towards smokers looking to kick the habit.

However, a new report by the Centers for Disease Control suggests that the e-cigarette is gaining favor among teens, too.

According to the CDC report, the number of U.S. middle and high school students who have tried e-cigarettes more than doubled from 2011 to 2012.

"That's an alarming increase," said Dr. Ashok Kumar, UT Medicine family physician. "And it's really concerning people like me, who want people to be healthy and to not develop this habit."

E-cigarette users inhale vaporized pure nicotine, not the cancer-causing contaminants you find in regular cigarettes.

However, Kumar said e-cigarettes containing nicotine can also be harmful to the heart and body, not to mention the fact that it is addicting.

"People think this is not harmful because they think they are not burning a cigarette and there is no smoke," said Kumar. "But what is happening is that you have a nicotine, which is very addicting, particularly to young children."

Kumar runs a program "Tar Wars," where he and his medical students go out to local schools encouraging them not to smoke and he said in those visits, he's getting questions about e-cigarettes from students as young as fifth-graders.

"People say they are not targeting kids," he said. "But ... you see all these (different) flavors, which are very interesting for the children."

Right now, there are no laws in Texas regarding the sale of e-cigarettes. New Jersey is the only state that currently bans the the sale of these products to minors.

Kumar said for now, e-cigarettes are not regulated, as far as how much nicotine is in each cigarette or if there are any other contaminants in the product.

However, he said it is something the FDA has been looking into in recent years.