Neurogenesis in the olfactory bulb of rodents continues into maturity and has been implicated in olfactory memory. The extent to which adult neurogenesis contributes to olfactory bulb function in humans is unclear, however. The number of neuroblasts migrating to the human olfactory bulb decreases sharply after birth, and here the authors used carbon dating to show that levels remain extremely low throughout life. This work highlights an important difference between humans and rodents in the role of neurogenesis in olfactory bulb function.