This is a big question, since most of the public conversation about smoking focuses on how the habit is bad for you. So do a little research on the health effects of smoking and fill your kids in on the dangers. For example, smoking increases risks of heart disease and stroke by two to four times [source: CDC]. It can cause various forms of cancer, including lung, larynx, stomach and throat cancer. It can also cause emphysema and other chronic breathing diseases. Add all those health risks up, and smoking is responsible for one out of every five deaths in the United States every year [source: CDC].
But while it's important to talk about the health risks of smoking, you're not as likely to get through to kids if you just spout off a lot of statistics about disease rates. Kids tend to think in the short term. Things like cancer, heart disease and strokes can seem too abstract and distant to really hit home. So make sure you talk about some of the immediate health effects of smoking [source: McCoy]. For example, they will have shortness of breath and frequent coughing. If your kid enjoys sports or other physical activities, explain that smoking will decrease their stamina and make it harder for them to do as well as they used to [source: McCoy]. Tell kids that smoking stains teeth, also, and leaves breath and hair smelly [source: National Health Information Center]. Bad breath might be a bigger worry for a lot of kids than getting sick in another 40 or 50 years.