You got an ‘F’ in sex

A boy asks his mother her age.
She replies, “Gentlemen don’t ask ladies that question.”

Boy then asks his mother how much she weighs.
Again his mother replies, “Gentlemen don’t ask ladies that question.”

The boy then asks, “Why did Daddy leave you?”
To this, the mother says, “You shouldn’t ask that,” and sends him to his room.

On the way, boy trips over his mother’s purse. When he picks it up, her driver’s license falls out. Boy runs back into the room yelling, “I know all about you now. You are 36 years old, weigh 127 pounds and Daddy left you because You got an ‘F’ in sex!”