You could smoke all your life and never be greatly affected. You could smoke just throughout your teens and still end up with cancer. It’s luck of the draw I’m afraid. When I was in hospital in the summer, a doctor told me that the lungs don’t get better after you stop smoking. I have become very skeptical of various scientific revelations. It is indeed magical, but in the sense that we are wonderfully made. Stop meddling. It’s like proving to your landlord that you won’t have problems paying rent by showing that your income is at least three times the amount of rent due. If you don’t have the money, maybe you just shouldn’t do it.