In biology, the physical differences between organisms of the same type, for example two humans, originate from so-called developmental noise stemming from probabilistic collisions between reacting molecules and environmental conditions in cells during the early stages of the organism’s growth. Generally, mechanisms are in place to prevent biological noise from resulting in incorrect organismal developments. Makoto Sato from Kanazawa University and colleagues have now discovered that a particular biochemical signaling pathway contributes to noise canceling in the differentiation process of neural stem cells—the self-renewing cells that play an important part in the development of the nervous system of animals during the embryonic stage.