You scratch my back, I scratch yours
There was once a white missionary who was sent into deep Africa. One day, there was a big commotion when a semi white baby was born. No one has an inkling how this could happened except one fine young cowherd. He stepped forward and volunteered his explanation but was pulled back by the missionary. The missionary pointed out his herd that was grazing and said "You see all those cows out there are all white and how come there is semi black one in the midst of them." The young man whispered into the missionary's ear "Ok Ok, if you promise not to tell about the cow, I will not tell about the baby."