Hollywood once wrote its moral rules into a production code.

How the Hays Code controlled what reached theaters

The Hays Code was Hollywood’s production rulebook, formally known as the Motion Picture Production Code. Although adopted in the 1930s, it became rigorously enforced in 1934. Studios agreed to submit films for approval because a movie without the industry’s seal could struggle to secure bookings in theaters. That leverage made the code more than a list of suggestions: it could shape a script before filming or require changes before release.

Its rules sought to keep screen stories within a narrow moral framework. They barred depictions of interracial romance—described in the code as “miscegenation”—and restricted profanity and sexual content. Even married couples were generally not to be shown sharing a bed. The limits affected more than what viewers saw: filmmakers often had to imply adult subjects through dialogue, editing, or a suggestive detail rather than depict them directly.

From prohibition to audience ratings

By the 1960s, the code’s blanket restrictions were increasingly difficult to apply to films aimed at changing audiences. In 1968, the Motion Picture Association introduced a voluntary ratings system. Instead of requiring every film to meet one set of content rules, it classified films by suitability for different audiences, giving parents and moviegoers guidance while allowing filmmakers to include material the old code would have barred.

That was a change in the mechanism of control, not an end to it. A rating could affect who chose to see a film, and studios still had commercial reasons to consider how content might limit its audience. The question shifted from “Can this be shown at all?” toward “Which viewers should this film be for?”

Why the system drew criticism

Ratings also made judgments about content visible—and debatable. Critics argued that the board could treat graphic violence more leniently than nudity, suggesting that its standards did not weigh all kinds of adult material equally. The shift left Hollywood with more room to tell stories, but also made the rating itself a powerful signal: one classification could influence a film’s marketing and the audience likely to find it.