This book examines the link between population growth and environmental impact and explores the implications of this connection for the ethics of procreation. In light of climate change, species extinctions, and other looming environmental crises, Trevor Hedberg argues that we have a collective moral duty to halt population growth to prevent environmental harms from escalating. This book assesses a variety of policies that could help us meet this moral duty, confronts the conflict between protecting the welfare of future people and upholding procreative freedom, evaluates the ethical dimensions of individual procreative decisions, and sketches the implications of population growth for issues like abortion and immigration. It is not a book of tidy solutions: Hedberg highlights some scenarios where nothing we can do will enable us to avoid treating some people unjustly. In such scenarios, the overall objective is to determine which of our available options will minimize the injustice that occurs. This book will be of great interest to those studying environmental ethics, environmental policy, climate change, sustainability, and population policy.