Emily Oster of the University of Chicago and author of Expecting Better talks with EconTalk host Russ Roberts about her book on pregnancy and the challenges of decision-making under uncertainty. Oster argues that many of the standard behavioral prescriptions for pregnant women are not supported by the medical literature. The conversation centers around the general issue of interpreting medical evidence in a complex world using pregnancy advice as an application. Alcohol, caffeine, cats, gardening and deli-meats and their effect on pregnant women are some of the examples that come up. The conversation closes with a discussion of Oster's work on hepatitis-B and the male-female birth ratio.