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The Science of Replaceable Parts, with Mary Roach

2025-12-20 Science & Technology
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StarTalk
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Description

Are our parts replaceable? Neil deGrasse Tyson, Chuck Nice, & Gary O’Reilly sit down with bestselling author Mary Roach, who discusses her newest book, Replaceable You, and the quest to grow organs, build parts, and engineer the human body. The discussion begins with an exploration of the human body as a complex machine and how far medicine has progressed in the replacement parts business, a practice dating back to 1500 BC. We look at pop culture, where shows like The Six Million Dollar Man and The Bionic Woman gave us the word bionic and the dream of being built better, stronger, faster. Mary shares anecdotes from her book, including a deep dive into Iron Lungs from the polio era and the difficulties of modern prosthetics, particularly hands. The conversation takes a historical turn as we look at nose replacement, which has been a necessity since nasal mutilation was a popular punishment for crime. Roach shares stories of an army surgeon who designed a Groucho Marx-style nose on a pair of glasses, and earlier surgeries requiring patients to keep their heads immobilized with a flap of tissue tethered to their own arm. Next, we turn to bionics and organ replacement. They discuss the challenges and triumphs of modern prosthetics, including osteo-integration and the issue of infection. The biggest obstacle in whole-organ transplantation is rejection. This leads to a discussion of xenotransplantation (using pig organs), the necessity of genetic editing to remove certain proteins, and chimerism: growing human organs inside pigs for personalized spare parts. Finally, Mary Roach reveals a bizarre chapter from her research: a surgeon who used a man’s middle finger to recreate his penis after cancer, a moment that prompts Chuck Nice to question the limits of surgical innovation. They wrap up by looking at 3D-printed organs and whether it could be accelerated by AI. Is this the road to immortality, or simply better medical care? Thanks to our Patrons Hubert Górecki, Michele and David, Antonio, Luigi, Normie, Ronald Stephens, Jessica Shawley, Michelle Harris, Angel Cueva Hernandez, S MB, Tony Pryor, Mike LaHaye, Samuel Ahn, Kendrick Frison, Lori Harting, David Aldrich, allen chen, Mark McDuff, daketchek, Nathan Boorom, Steven G., Emilio Lopez Hatt, Leslie Lantz, Ken Gelwix, Nick4547, James G Avdoulos, Astitva, Dana Lewis, T, Claire Davis, Richard S, Glen Brown, Sierra Tornabeni, Sue Peters, Stefano Ete, Shawn Sellers, Adriane Underwood, jason jones, Charles, Infuriated Jurijcorn, Que the music, Jeremy Hunter, Sampson, Bhushan Nene, Paul Kruger, Sean Wyatt, Carlos Pelayo, Joey Mack Newell, Alex lakovidis, Cookiehart, W Hollifield, Davi Martin, Hd4122, Shon Bucklin, Tony Taveras, aeonoku, Shawn Browning, ben dewrance, Black____Monday, J Hardman, Erik Krasguidotti, Thegayestmanalive, YBenali, Richard Green, Brian Charbonneau, Syronn Terry, Bruce Griffith, Amir, Tom Pritchett, Guido Vermeulen, Povvy, Sigurbjorn B. Larusson, David Paul, Kristoff De Maeseneer, Scott Strum, Roni Riabtseb, Monopolyworld, Naeem C, Jayson Cowan, and Steph Dean for supporting us this week. Timestamps: 00:00 - Introduction: Mary Roach 05:09 - Writing Replaceable You 09:02 - Why Haven’t We Figured Out Regenerative Medicine 11:16 - Replacement Noses 16:22 - The Golden Ratio 18:47 - How Close Are We to the Bionic Man? 21:31 - Osteointegration 24:36 - Organ Replacement 34:48 - The Finger Penis 39:17 - 3D Printing Organs 43:53 - Ethics 45:52 - A Cosmic Perspective Check out our second channel, @StarTalkPlus Get the NEW StarTalk book, 'To Infinity and Beyond: A Journey of Cosmic Discovery' on Amazon: https://amzn.to/3PL0NFn Support us on Patreon: https://www.patreon.com/startalkradio FOLLOW or SUBSCRIBE to StarTalk: Twitter: http://twitter.com/startalkradio Facebook: https://www.facebook.com/StarTalk Instagram: https://www.instagram.com/startalk About StarTalk: Science meets pop culture on StarTalk! Astrophysicist & Hayden Planetarium director Neil deGrasse Tyson, his comic co-hosts, guest celebrities & scientists discuss astronomy, physics, and everything else about life in the universe. Keep Looking Up! #StarTalk #NeildeGrasseTyson

Top Comments (10)

@Ashleyramirezlv 2025-12-21

I love this episode. I lost my left leg above the knee in a car accident 2 years ago. I currently use a prosthetic that requires me to insert my remaining limb into it. By next summer I’ll have a surgery called Osseointergration . A titanium rod will be implanted into my femur and eventually I’ll be able to just lock into my microprocessor knee. I’ll truly be a bionic woman 😬🦿

180 18 replies
@colorlysimmxX 2025-12-21

I really appreciate Gary refocusing the group on Mary's book, which he actually read.

71 4 replies
@ashmidnyt 2025-12-20

Mary has a great sense of humor.

38
@johnstevens3598 2025-12-20

This past year I had a skin graft to re-build the skin covering of a leg wound, about the size of a quarter. The doctor did not use skin from my body. The graft came from a lab grown stem cell "pad" of placenta, I was told. There has been no rejection, no stitches, no scarring, no drug protocol. The area has "regrown" and has become part of the skin covering this area. The only way to tell is that graft area is a little mottled in texture compared to the surrounding area when touched. At first, I assumed that this was a long proven method and not all that amazing. But after listening to this podcast, I get the idea that this is a big step forward in medical practice and I am thankful that this is available to help treat body recovery.

34 3 replies
@UndergroundMonk 2025-12-20

The Fifth Element had one of the coolest scenes of organic 3D printing.

29 5 replies
@sailorwolfe6127 2025-12-21

i have never laughed so hard during one y'alls podcasts hahaha please have this guests back and please keep providing us all with the knowledge and wisdom you continual share!

25
@geoffreykail9129 2025-12-20

Mary Roach is amazing and one of your best guests. Very enjoyable and enlightening. Thank You! Chuck and Gary really add to the whole experience

21
@andersoncubillos 2025-12-27

I've become addicted to this show, especially when the full panel is on set.

11
@xXximanemogirlxXx 2025-12-31

Time stamp 45:12 ish) To clarify Gary was talking about a form of clone farming, which is usually regarded as unethical as that clone will almost always have it's own memory and experience therfore be it's own person. Now cloning an individuals orgins alone would typically be fine as long as you could properly develop them in a test tube or tank of some kind. I actually read a book once about this country (a fictional book that was syfi based) where the ruler had lived something like 2-300 years if I remember correctly, because he would clone himself and raise the clones until he could replace his organs with young healthy ones. Eventually one of the clones ends up running around and realizing the original is a bad person overthrow him. Unsurprisingly the unethical way he farmed himself lead to the leader being over thrown by a better younger kinder version of himself who had truly become their own person (because in reality just sharing the exact same DNA does not make you the exact same person) its a bit more morbid of a way to use clones than the way they are used in "clone wars" I wish I could remember the name of that book damn I will look it up in a second see if I can find it if I do I will post it in my reply section for those interested.

3
@shermanartcreativeservices1868 2026-03-12

that look on Neil's face when Gary said, "you know a lot about this!" OMG I just about DIED. LOL

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