Have you ever hesitated before diving into a pool, trying to remember if it’s been at least 30 minutes since you ate? Or not itched a mosquito bite for fear that scratching would only make it worse? Health myths buzz around summer pastimes such as swimming, camping, hiking and picnicking like so many gnats.

People have a hard time letting go of word-of-mouth wisdom, even when faced with good evidence to the contrary.

“Myths stick with us because they make sense to us, on some level,” says Indianapolis pediatrician Rachel C. Vreeman. “When you’ve heard them from your grandmother and mother and important adults in your life, you believe those things.”