OK, so it's not a joke, and really happened. A friend of mine worked as a midwife in Appalachia. (For those of you not from around these parts, Appalachia is an economically-depressed area in the Appalachian Mountains. The term hillbilly comes from there.)
One day, she's at somebody's home, delivering a baby, and hears a commotion outside. The sister of the mother-to-be is in the room, assisting, so the midwife asks her to find out what all the noise is about, so the young lady leaves the room and goes outside. A few minutes later, she comes back in and tells the midwife it's nothing to be concerned about. The midwife asks, "Why, what's going on?"
The ruckus was the brother and father of the mother-to-be, out in the front yard,fighting, arguing over which of them was the father.