When summer break rolls around, the sunshine and outdoors beckons. But some kids would rather remain plugged in indoors. However, too much screentime is truly hazardous for their health.

Dr. Douglas Gentile, an award-winning research scientist, educator, author and associate professor of developmental psychology at Iowa State Uni­versity, has extensively studied the subject of kids and screentime.  

He said parents tend to be more concerned about the amount of screentime kids are exposed to versus the content, but both actually matter.

“The amount of screentime is related to things like poorer school...