@farmerman,
There was no understanding of the issue in the post in which you raised the matter. I wasn't even saying that the point you raised about hereditary cancer was invalid. It had no beef, as usual. Just what you had read somewhere.
I've seen stuff on the matter. How do we know it was smoking? What do we say to those whose grandfathers were heavy smokers? As many were. You might be giving them anxiety attacks about something they can do nothing about. It is a matter to create anxiety. And how many non- smokers are there now who were heavy smokers when they did the deed.
If you are so concerned about our grandchildren why are you not out campaigning to reduce the debts we are piling on to them and which they can justifiably refuse to pay. Don't you think there should be a screening programme whereby grandchildren of heavy smoking grandfathers at the time of the deed can be tested early.
What do the grandchildren of non-smoking grandfathers get? We all get something or other. Possibly they get higher marks in exams. Nicotine is a known brain stimulant.
I believe that grandchildren and children of grandfathers with long, thin noses are more prone to artereosclerosis. But I haven't read it anywhere. I think arteries are as likely to show physical differences as external features do. ( The long, thin nose was a metaphorical flight of fancy--don't read it literally.) Liquids passing through convoluted pipes. Thousandths of an inch.