In a historic first, a kidney from a genetically modified pig was successfully transplanted into a human. Researchers hope for more of this kind of transplant because there aren’t enough human organs for the thousands in need. But putting animal tissue into a human is complicated. William Brangham discussed that with Dr. Leonardo Riella of Massachusetts General Hospital. Stream your PBS favorites with the PBS app: https://to.pbs.org/2Jb8twG Find more from PBS NewsHour at https://www.pbs.org/newshour Subscribe to our YouTube channel: https://bit.ly/2HfsCD6 Follow us: TikTok: https://www.tiktok.com/@pbsnews Twitter: http://www.twitter.com/newshour Instagram: http://www.instagram.com/newshour Facebook: http://www.pbs.org/newshour Subscribe: PBS NewsHour podcasts: https://www.pbs.org/newshour/podcasts Newsletters: https://www.pbs.org/newshour/subscribe