A professor travels to Africa to live with a primitive tribe. He spends years with them, teaching them all about the wonders of science and mathematics. One day, the Chief's wife gives birth to... a white child! The word spreads, and the entire tribe is in shock. The chief pulls the professor aside and says, "Look, you're the only white man we've ever seen around here, and this woman just gave birth to a white child. It doesn't take a genius to figure out what happened!" The professor replied, "No, Chief. You're mistaken. What you have here is a natural occurrence, what we in the civilized world call an albino! Look at that field over there. All of the sheep are white except for one black one. Nature does this on occasion." The chief was silent for a moment, then said, "Tell you what. You don't say anything more about that sheep and I won't say anything more about that white child."