It’s easy to think that the way we think about children and parenting is the way it’s always been — the birth of a child is accompanied by the expectation that that baby will grow up happy, healthy, and become an adult. However, a mere century ago that wasn’t necessarily the case. So what changed?  How has the role of parenting transformed?  Dr. Perri Klass, author of the new book "A Good Time to Be Born", joins us to talk about the social, and medical, events that transformed childhood and parenting.