A grade school teacher was asking his pupils what their parents did for a living. "Tim, you be first. What does your mother do all day?"
Tim stood up and proudly said, "She's a doctor."
"That's wonderful. How about you, Amy?"
Amy shyly stood up, scuffed her feet and said, "My father is a mailman."
"Thank you, Amy" said the teacher. "What does your parent do, Billy?"
Billy proudly stood up and announced, "My daddy plays piano in a whorehouse."

The teacher was aghast and went to Billy's house and rang the bell. Billy's father answered the door. The teacher explained what his son had said and demanded an explanation. Billy's dad said, "I'm actually a system programmer specializing in TCP/IP communication protocol on UNIX systems. How can I explain a thing like that to a seven-year-old?"