A sophisticated system of “social control” operating between neighboring cells allows embryos to protect the purity of their pluripotent cell population, which is able to generate all body tissues. This system works through the elimination of cells that begin to differentiate prematurely, in a process mediated through “cell competition” based on the expression levels of the gene Myc. This control system is important for pluripotency during the development of mammalian embryos, and is described for the first time in Developmental Cell by researchers at the Centro Nacional de Investigaciones Cardiovasculares (CNIC).