What does “natural” really mean when it comes to sex, pregnancy and parenting? Dr. Robert Martin, emeritus curator of biological anthropology at Chicago’s Field Museum, discusses reproduction from the basic biology of sperms and eggs to the complexities of birth control and assisted fertility. Martin presents a look at our evolutionary past in terms of child-rearing practices and other aspects of reproduction, offering insights into what worked, what didn’t, and what it all means for the future of our species.