A man meets a woman at a bar and they go to her place.

They're undressing and he drops his trousers. She points to his messed up knees and asks what happened. He says 'when I was young I contracted kneesles'. She says 'you mean measles'. He says 'no, I actually got kneesles'.

She shrugs and continues undressing. When he removes his socks she looks at his sorry toes and asks about them. He says 'shortly after the kneesles, I contracted toelio'. She says 'you mean polio?'. He says 'no, I got toelio'.

She shrugs it off, until he drops his shorts. She looks again and says 'don't tell me - smallcox'.