An old couple had four sons. The odd thing was that the older three had red hair, light skin, and were tall; while the youngest son had black hair, dark eyes, and was short.
The old man eventually took ill and was lying on his deathbed when he turned to his wife and said, "Honey, before I die, be totally honest with me: is our youngest son really my child?"
The wife replied, "I swear on everything that's holy that he is your son."
With that, the old man uttered a contented sigh and passed away.
As the wife wiped away a tear, she muttered, "Thank God he didn't ask about the other three!"