Little girl: "Mom, how old are you?"
Mom: "Now honey, you aren't supposed to ask women those kinds of questions..."
Little girl: "Well, how much do you weigh?"
Mom: "Now honey, thats not a very nice question to ask people either."
The little girl is frustrated, but continues asking questions... "Mom, why did you and daddy get divorced?"
Mom: "Now dear, that's not something you should ask. I'll talk to you about it when you get older."

When mom finally drops the little girl off at school, the little girl meets up with one of her friends. They start talking and she says, "Well, I didn't find out anything about my mom... she won't answer any of my questions!"
The friend says, "Well, you should look on her drivers license. Those are supposed to tell everything about a person. Thats what 'identification' means..."

That night, the little girl finds her mom's drivers license and finds all the answers she wanted. She goes to tell her mom...
"Mom, I found out how old you are! You are 42!"
Mom: "Wow, thats right!"
Little girl: "And I found out how much you weigh! 150 pounds!"
Mom: "Wow! Right again!"
Little girl: "And I know why you and daddy got divorced!"
Mom: "...oh really..."
Little girl: "Yup, it's cause you got an "F" in sex!"