n March 16, A transplant-surgery team at Massachusetts General Hospital successfully transplanted a modified pig kidney into a human: 62-year-old Richard Slayman. The groundbreaking, four-hour surgery was the culmination of years of work transplanting kidneys from a specially bred group of pigs—genetically modified to more closely resemble those of humans—into primates. Encouraged by those results, the team at Mass General Brigham was confident it was time to test the pig
