This dissertation provides a defense of the normative intuition known as the Procreation Asymmetry, according to which there is a strong moral reason not to create a life that will foreseeably not be worth living, but there is no moral reason to create a life just because it would foreseeably be worth living. Chapter 1 investigates how to reconcile the Procreation Asymmetry with our intuitions about another recalcitrant problem case in population ethics: 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. Chapter 2 attempts to connect my defense of the Procreation Asymmetry to corresponding evaluative claims about the goodness of the outcomes produced by procreative decisions. I propose a view, the `biconditional buck-passing view of outcome betterness', according to which facts about the comparative goodness of outcomes are a function of our reasons for bringing about one outcome rather than another under certain conditions. This enables me to derive an Evaluative Procreation Asymmetry from the corresponding normative claims established in Chapter 1. The biconditional buck-passing view also provides me with a principled basis for challenging a version of the Independence of Irrelevant Alternatives Principle. This, in turn, permits me to provide a novel solution to another famous problem in population ethics: Parfit's Mere Addition Paradox. Finally, in Chapter 3, I rebut some key objections to the Procreation Asymmetry by showing that upholding it does not commit us to anti-natalism and that it is compatible with a moral concern for the long-term survival of humanity. / Philosophy