Neither. If you're going to tell someone (doesn't have to be a child) a story with a life lesson or moral of some kind in it don't use some convenient outlet. Just tell a story you personally experienced.
Example: Lying
That time when you lied to your mom and blamed your sibling when a glass broke. Mom found out the truth and spanked you.
vs.
When you lied to a teacher/guidance councilor/principal/whomever to protect a friend/family member/whomever.
Theme: Lying can be both good and bad. Everyone lies or has lied at some point or another. It doesn't make someone good or bad since everyone has their reasons for doing so.
The best place for wisdom and life lessons for a child is their parents and/or people who surround him/her. Its much more meaningful to hear a true story from someone the child knows than from any (potentially) made up book. Its important to note such stories are meant to supplement his/her own experience and not replace it.