Substitute

Little Johnny's teacher was asking all the kids in the class what their parents did for a living.

Little Mary got up and said "my Dad is a pilot, and my Mommy is an architect."

"Great," said the teacher.

Michael got up and said " my Dad is a Doctor, and my Mom is a housewife."

"Good," said the teacher.

Johnny was last in the class and when he got up he said: "My Mommy, she is a substitute."

Knowing better about his background and always striving to correct the kids, the teacher said, "you mean she is a Prostitute."

"No," Said Johnny, "my sister, she is a Prostitute, but when she does not feel well, my Mommy substitutes."