The mother's in the delivery room, and as was the custom of the time, the father's in the waiting room.
The mother wears a false set of front teeth, because of a car accident in college; at the doctor's insistence, the teeth have been removed, to the mother's chagrin. It's her first child, so there's a good deal of nervousness in the room.
The baby arrives--a fine healthy baby boy with lots of dark hair. The doctor slaps his butt to remove the mucous and hands him to the mother.
"Well, Mrs. -----, how do you feel?" the doctor asks.
The mother stares at him, and intones, "I'll tell you how I feel if you give me my fucking teeth back."