The kids at my kid's school were insisting to her that men had one less rib than women did, recently. Nor would they take any evidence she presented as proof to the contrary (anatomy textbooks, Wikipedia, her suggestion that they consult a biology professor -- she knows a famous one, who works at our university). Nope. God says it, they believe it, that settles it.
I suggested she send them this link.
"Ma!" she said.