Nine in 10 smokers pick up the habit before the age of 18, according to the website Teens Health. The most common reasons are that it makes them feel more independent, look older and it can serve as a means for rebelling against authority figures. Peer pressure and having friends who smoke have an influence on young people. If a child in a social circle starts experimenting with tobacco, it's all too easy for him or her to lead peers into smoking. Moreover, the American Cancer Society points out that kids whose parents smoke are much more likely to pick up the habit than those with non-smoking parents. Studies have found that parents who react to smoking as a socially acceptable behavior -- even if they don't smoke -- can leave the door open for their children to experiment with tobacco.