Making the most powerful type of cell in the world used to require destroying human embryos, and controversies over harvesting the cells have slowed research. But now scientists at the RIKEN Center for Developmental Biology in Japan have figured out a way to make them by simply soaking animal cells in an acidic solution for half an hour. Tests in mice proved the cells worked, growing into tissues and organs. Stem cells can turn into virtually any other kind of cell, with the potential to regenerate the body and treat diseases like Alzheimer’s. Tests must now move on from mice to men.