Jason Howell and Megan Morrone talk to Dr. Jenny Radesky about kids and screen time. In December we talked about our concerns about Facebook's new messaging app for kids. Now a group of 100 pediatricians, psychiatrists, educators, and other experts have sent a letter to Facebook CEO Mark Zuckerberg, urging him to discontinue the Messenger Kids. One of the experts who signed that letter is Dr. Jenny Radesky, a developmental-behavioral pediatrician and lead author of the latest guidelines on media and young minds from the American Academy of Pediatrics. She answers our questions.