"Vaccines made using WI-38 cells have immunized hundreds of millions of people against rubella, rabies, adenovirus, polio, measles, chickenpox and shingles. In the 1960s and 1970s, the cells helped epidemiologists to identify viral culprits in disease outbreaks. Their normality has made them valuable control cells for comparison with diseased ones. And at the Wistar Institute, as in labs and universities around the world, they remain a leading tool for probing the secrets of cellular ageing and cancer. “Here’s a clump of cells that has had an enormous impact on human health,” says Paul Offit, chief of the division of infectious diseases at the Children’s Hospital of Philadelphia. “These cells from one fetus have no doubt saved the lives of millions of people.” Few people, however, know the troubled history of the cells — one that may offer lessons for modern researchers seeking to work with human tissues. Six years after deriving his famous strain, Hayflick made off with stocks of the cells and later started to charge for shipping them, prompting an epic legal battle with the US National Institutes of Health (NIH) in Bethesda, Maryland, about who owned the cells. That struggle nearly destroyed Hayflick’s career and raised questions about whether and how scientists should profit from their inventions."