Not since the atomic bomb has a technology so alarmed its inventors that they warned the world about its use. Not, that is, until the spring of 2015, when biologist Jennifer Doudna called for a worldwide moratorium on the use of the new gene-editing tool CRISPR — a revolutionary new technology that she helped create — to make heritable changes in human embryos. The cheapest, simplest, most effective way of manipulating DNA ever known, CRISPR may well give us the cure to HIV, genetic diseases, and some cancers, and will help address the world’s hunger crisis. Yet even the tiniest changes to DNA could have myriad unforeseeable consequences — to say nothing of the ethical and societal repercussions of intentionally mutating embryos to create “better” humans. Doudna joins Walter Isaacson in conversation about gene editing and the unthinkable power to control evolution.