This paper sketches a theory of the reason-giving force of well-being that allows us to reconcile our intuitions about two of the most recalcitrant problem cases in population ethics: Jan Narveson's Procreation Asymmetry and Derek Parfit's Non-Identity Problem. I show that what has prevented philosophers from developing a theory that gives a satisfactory account of both these problems is their tacit commitment to a teleological conception of well-being, as something to be ‘promoted’. Replacing this picture with one according to which our reasons to confer well-being on people are conditional on their existence allows me to do better. It also enables us to understand some of the deep structural parallels between seemingly disparate normative phenomena such as procreating and promising. The resulting theory charts a middle way between the familiar dichotomy of narrow person-affecting theories and totalist or wide-person affecting theories in population ethics.