Parents in the United States are spending more time and energy than ever to ensure that their children turn out happy, healthy, and successful. But what does the evidence suggest about the impact of their efforts? Economist Bryan Caplan (and the author of "Selfish Reasons to Have More Kids") argues that, despite our intuition that parenting choices affect children's life outcomes, there's strong evidence to the contrary. Bryan and Julia discuss his case, and explore what that means for how people should parent and how many kids they should have.