Will i develop lung cancer if my grandparents smoked a lot and i spent a lot of time with them?

No: Children exposed to second-hand or passive smoke have a higher incidence of otitis media (ear infections), respiratory tract infections, and wheezing. No clear evidence suggests a higher risk of lung cancer.

Not so fast!: Smoking causes lung cancer. Second hand smoke, even from gram and gramps, can increase your risk, but this is why smoking bans are in effect in most states, and smoking sections (restuarants and planes) are a thing of the past. You may not be able to get friends and family to quit, but you can limit your exposure.

Not likely: If you are a non-smoker/never smoker (<100 cigarettes in a lifetime), and your second hand smoke exposure is low, then your risk compared to the general population should not be elevated.