On Nature vs Nurture

Crowley, the demon, gives his two cents on the nature vs nurture debate.

"But genetics-"
"Don't tell me about genetics. What've they got to do with it?" said Crowley. "Look at Satan. Created as an angel, grows up to be the Great Adversary. Hey, if you're going to go on about genetics, you might as well say that the kid will grow up to be an angel. After all, his father was really big in Heaven in the old days. Saying he'll grow up to be a demon just because his dad became one is like saying a mouse with its tail cut off will give birth to tailless mice. No. Upbringing is everything. Take it from me."

Good Omens: The Nice and Accurate Prophecies of Agnes Nutter, Witch