Chapter 3 examines social contract theories in their two dominant contemporary forms: contractarianism and contractualism. Contractarianism, as developed by David Gauthier, resembles a moral libertarianism by imposing minimal duties, making it difficult to condemn nearly any commonsense sexual wrongdoing. Like consequentialism, it permits token cases of bestiality, necrophilia, incest, and cannibalism. However, unlike consequentialism, it lacks a perverse obligation, as it struggles to ground any altruistic duties at all. Contractualism, in contrast, aligns more closely with moral commonsense in recognizing altruistic obligations. Following Thomas Scanlon’s formulation, contractualism grounds moral principles in what no one could reasonably reject. Yet this framework also leads to many of the same strongly counterintuitive conclusions as contractarianism, and adds duties of sexual philanthropy when a refusal to engage in sex could be reasonably rejected by another.