Is this funny joke. Tell me what you think funny?

A Pole, an Italian, and a Jew, all first-time fathers, are pacing nervously in the maternity ward waiting room when a nurse rushes out of the delivery room holding a black baby. "Is it yours?" she asks the Italian. "Certainly not," he retorts. "Yours?" she asks the Pole, who vigorously denies paternity. "How about you?" she asks the Jew. "Maybe," he says glumly. "My wife burns everything."