Yes Brian, there's no doubt that smoking contributes or causes cancer, heart disease blah, blah, blah. No argument on that. However, to the best of my knowledge, there is no test available that would allow a doctor to definitively state that an individual's cancer was caused by second hand smoke or directly smoking just as they can't definitively state that an oral cancer was caused by consuming alcohol. It is entirely possible for an individual to smoke, drink and have HPV and develop cancer due to another cause. On a side note, I see in the news today that third hand smoke is now becoming an issue ie. smoke particles in carpet apparently contributing to cancer in crawling infants etc.