Teenagers are more likely to start smoking if their parents light up as well.
Harvard researchers confirmed the link after looking at the smoking habits of over 550 adolescents and their parents.
Teens were most likely to smoke if their parents smoked around them before the age of 13 and still smoked regularly.
Fathers who smoke were more likely to influence their teenage sons than their daughters.
Researchers hope these results will encourage parents to quit -- in hopes of keeping their children from picking up the habit.