In this episode of Talk Nerdy, Cara is joined by celebrated science writer Carl Zimmer, author of "She Has Her Mother's Laugh: The Powers, Perversions, and Potentials of Heredity." They discuss the promises of modern genetics research and applications, as well as the dark history of the eugenics movement. Carl also tells of his personal journey to uncover the secrets that lie within his own genome. Follow Carl: @carlzimmer.