This chapter considers the reasons why accusations of sexual impropriety, commonly levelled at religious leaders, are commonplace, and what factors make them powerful. That accusations of sexual impropriety are common in religious conflicts, even when the accused are puritans, suggests that the defamation has some value other than (or beyond) its accuracy. This chapter explores the possible reasons why one or both sides in a religious quarrel will try to defame opponents by accusing them of sexual transgression. First, such claims are invited by the priority that religions give to the management of sexuality, especially in modern societies where religion controls little else. Second, when religious zealots accuse others of moral laxity, they invite retaliation on the same ground. Third, while only the religiously committed will be moved by arguments about doctrine, most people will have some interest in charges of sexual impropriety. Finally, there is the simple point that, while circumstances render many defamations implausible or at least contestable, accusations of sexual transgression are always inherently plausible. Those so defamed may insist that they did not do it, but they cannot deny that they could have done it.