A missionary gets sent into deepest darkest Africa and goes to
live with a tribe there. He spends years with the people,
teaching them to read, write and the good Christian ways of
the white man. One thing he particularly stresses is the evils
of sexual sin. Thou must not commit adultery or fornication!!

One day, the wife of one of the Tribe's noblemen gives birth
to a white child. The village is shocked and the chief is sent
by his people to talk with the missionary. "You have taught us
of the evils of sexual sin, yet here a black woman gives birth
to a white child. You are the only white man that has ever set
foot in our village. It doesn't take a genius to work out what
has been going on!"

The missionary replies: "No, no, my good man. You are mistaken.
What you have here is a natural occurrence - what is called an
albino. Look to thy yonder field. See a field of white sheep,
and yet amongst them is one black one. Nature does this
on occasion."

The chief pauses for a moment then says, "Tell you what,
you don't say anything about the sheep, I won't say anything
about the white child."