Mr Smith calls the doctors surgery to get his wife's test results. The receptionist explains there has been a mix-up, they have 2 test results for Mrs Smith's and they got mixed up... one has Alzheimer's and the other has AIDS. Mr Smith says "Oh dear, what shall I do now". The receptionist replies, "Easy... drop your wife off in town, if she makes it home on her own.... don't have sex with her"