For centuries, humans have tried to repair and replace our body parts -- from brass noses and pig organs to today’s lab-grown tissue. So where do we stand now?  Sanjay sits down with author Mary Roach to discuss her newest book, Replaceable You: Adventures in Human Anatomy, which explores the wild history and newest experiments behind human “upgrades,” from 3D‑printed muscle to the ethics of elective amputation and what these innovations mean for our aging bodies.     Our show was produced by Jennifer Lai with assistance from Leying Tang.   Medical Writer: Andrea Kane Showrunner: Amanda Sealy Senior Producer: Dan Bloom Technical Director: Dan Dzula  Learn more about your ad choices. Visit podcastchoices.com/adchoices