The Hays Production Code was a censorship protocol created by politician Will Hays that lasted from 1930 to 1968. This code stated that :
- No picture shall be produced that will lower the moral standards of those who see it. Hence the sympathy of the audience should never be thrown to the side of crime, wrongdoing, evil or sin;
- Correct standards of life, subject only to the requirements of drama and entertainment, shall be presented; and
- Law, natural or human, shall not be ridiculed, nor shall sympathy be created for its violation.
Accompanying the three major tenets of the Hays Production Code was a list of "Particular Applications" drafted by a Catholic priest and accepted by Hays. These applications forbade a film to show things such as nudity, suggestive dance, ridicule of religion, drug use, homosexuality, childbirth and "excessive and lustful kissing."
In the late 1960s production companies refused to abide by the Hays Code, releasing films without their approval, leading to abandonment of the code. Jack Valenti, the new president of the Motion Picture Association of America, then created a new system that removed many of the Hays code's antiquated restrictions.
In November 1968 the new ratings system began with four categories: G, which was for general audiences or all ages; M for mature audiences with suggested parental guidance but still allowed for all ages; R for restricted audiences in which no one under 17 would be allowed without a parent; and X, with no one under 17 admitted.
The M rating was changed to PG for "Parental guidance suggested" and in 1984 that was separated into PG and PG-13. In the 1990s the X rating was replaced with the NC-17 rating. Also during this time, the MPAA instituted a system that would include content warnings for parents, to point out such things as violence, harsh language and nudity.