Religion

"Formed from Adam's side." But what, part of the intracostal muscle tissue?

That coupled with a bit of not quite right anatomy led to "rib."

Hanlon's razor--don't attribute to malice what can be adequately explained by stupidity. (Although it feels so much better to assume the other side isn't just in an error of fact, but an error of virtue and morality ... But that says more about the attributer, I guess, and information is always good to have.)