The truth: Sorry, but you'll need to look for another excuse to curb this annoying habit. There's no evidence that it leads to arthritis. In fact, people who crack their knuckles generally have healthier joints than those who don't. So should you encourage it? Nah. It's not the knuckle cracking itself that's protecting them against arthritis, but the fact that they tend to be more physically active than non-crackers, says Tyler Cymet, assistant professor of internal medicine at Johns Hopkins School of Medicine, in Baltimore, and the author of a recent study on joint cracking.
What you've heard: "If your child cracks his knuckles, he'll get arthritis later."