Historically, sexual morality and criminal law overlapped, and churches and states enforced sundry sex crimes. Today, new constitutional liberties and new reforms to family law and criminal law have dramatically reduced the roll of sex crimes and the roles of churches in maintaining sexuality morality. But sexual misconduct remains a perennial reality in modern societies, including notably within churches, and sex crimes inflict some of the deepest scars on their victims. Modern liberal states must thus maintain a basic standard of sexual morality in its criminal law as a restraint on harmful behavior and as a bulwark against a sexual state of nature where life is often "brutish, nasty, and short" for the most vulnerable. And liberal societies should encourage its citizens and churches to pursue a higher morality of aspiration that views sex and the sexual body as a special gift for oneself and others.
Witte, Jr., John (Tue,) studied this question.