Stop me if you've heard this one...

Here's a joke I heard over lunch today:

Little Billy asks his mother, “Mom, where do humans come from?”
His mother responds, “If you look in the Bible, we are all descended from Adam and Eve.”
Little Billy then goes to his father, and asks him the same question.
His father responds, “Modern science tells us that we are all descended from monkeys.”
Confused, Billy returns to his mother and tells her what his father said.
His mother thinks for a moment, and then responds, “The monkeys, that’s his side of the family.”