Scientists have long struggled to make pregnancy easier, safer, and more successful, and here, developmental and stem-cell biologist Magdalena Zernicka-Goetz takes us to the front lines of efforts to understand the creation of a human life. She has spent two decades unraveling the mysteries of development, as a simple fertilized egg becomes a complex human being of 40 trillion cells. Set at the intersection of science's greatest powers and humanity's greatest concern, Zernicka-Goetz reflects on her own unusual pregnancy and speculates on the future of fertility.