This chapter provides an account of the asymmetry in population ethics. The first half of the asymmetry is explicated by means of a person-affecting view, whereas the second half is established by means of a structural consistency constraint. This account can be integrated into a general theory that can handle (i) cases where there are externalities in that members of the original distribution are positively or negatively affected by bringing the miserable life into existence, (ii) cases in which one is concerned not only with bringing individual persons into existence but also groups of people, and (iii) situations in which it is uncertain whether an action will result in the addition of lives that are worth not living.