It's in the genes

Joe is an 80 year old man who goes in for a physical. The dr. can't believe what great shape he's in for a man his age and asks what his secret is. Joe says "I don't really have a secret but I do play 18 holes of golf every morning". The dr. says "Well, I think it's more than that. It's probably in your genes. How old was your father when he died?" Joe says "Who said he was dead"? The dr, is surprised that the father of an 80 year old is still alive. Joe says "He's 100 year old and in perfect health. In fact, he played 18 holes with me this morning". The dr. is shocked and says "I still think it's in the genes. How old was your grandfather when he died"? Joe says "Who said he was dead. He's 118 and and in great shape." The dr. is about to lose it and says "I suppose he played 18 holes with you this morning." Joe says"No, he couldn't go this morning. He's on his honeymoon. He married a 20 year old girl." The dr. says" It's none of my business, but why would a 118 year old man want to marry a 20 year old girl"? Joe says "Who said he wanted to?"