The pancreas is a key metabolic regulator. When pancreatic beta cells cease producing enough insulin, blood sugar levels rise dangerously--a phenomenon known as hyperglycemia--thus triggering diabetes. After discovering that other mature pancreatic cells can adapt and partly compensate for the lack of insulin, a team from the University of Geneva (UNIGE) demonstrates that the stem cells from which beta cells are derived are only present during embryonic development. This discovery puts an end to a long-standing controversy about the hypothetical existence of adult pancreatic stem cells that would give rise to newly differentiated hormone-producing cells after birth. The scientists also succeeded in precisely defining the ‘identity card’ of pancreatic endocrine cells, which is a promising tool for the production of replacement insulin-secreting cells. These results can be read in Cell Reports and Nature Communications.