This article discusses the story of Robert Pennington, the first person in America to receive a Xenotransplantation. In 1997, he faced acute liver failure and no human liver was available. His surgeons proposed hooking him up to a series of pig livers outside his body, which they hoped would filter his blood and keep him alive until a human donor was found. These pigs were transgenic--their organs had been genetically modified to be human compatible. For seven hours over three days, Robert was attached to a pig liver from a transgenic pig developed by biotech company Nextran. Then, a human liver became available. This procedure was done just weeks before such experiments were halted by the FDA because of fears of a pig virus spreading to humans. Pennington was one of a half dozen patients on a Phase 1 clinical trial whose lives were saved using pig livers.