Until the late 1960s, tens of thousands of children suffered crippling birth defects if their mothers had been exposed to rubella, popularly known as German measles, while pregnant; there was no vaccine and little understanding of how the disease devastated fetuses. In June 1962, a young biologist in Philadelphia, USA, using tissue extracted from an aborted foetus from Sweden, produced safe, clean cells that allowed the creation of vaccines against rubella and other common childhood diseases. Two years later, in the midst of a devastating German measles epidemic, his colleague developed the vaccine that would one day wipe out homegrown rubella.