There was this little kid who had a bad habit of sucking his thumb.
His mother finally told him that if he didn't stop sucking his thumb, he'd get fat.
Two weeks later, his mother had her friends over for a game of bridge.
The boy points to an obviously pregnant woman and says, "Ah, ha! I know what you've been doing!"
A young teenager comes home from school and asks her mother, "Is it true what Rita just told me? That babies come out of the same place where boys put their thingies?" "Yes, dear," replies her mother, pleased that the subject had finally come up and she wouldn't have to explain it.
"But then when I have a baby, won't it knock my teeth out?"