Movie review ratings began around the year 1966 in the United States when Jack Valenti was president of the Motion Picture Association of America (MPAA). This was a decade when there were changed American morals due to protesting, riots in the streets, women's liberation and the change of social traditions.

As always, the arts were impacted greatly by these changes in society, resulting in the emergence of a new type of American movie that tended to be more open, and less restrained.

these changes brought controversy, first exhibited in the film "Who's Afraid of Virginia Woolf," in which, for the first time on the screen, the word "screw" and the phrase "hump the hostess" were heard for the first time in a film. The MPAA's general counsel and team conferred, resulting in the deletion of the word "screw" and retention of the phrase "hump the hostess." Perhaps this was just the beginning of an unsettling new era in film.

Metro-Goldwyn-Mayer's film "Blow-Up" was in question because it was the very first time a major distributor was marketing a film with nudity, and the Production Code Administration (PCA) in California denied the seal of approval. The U.S. Supreme Court, in April 1968, upheld the constitutional power of states and cities, preventing the exposure of children to books and films that could not be denied to adults. This was the real blow-up between new social currents - the force of the film creators who were determined to make their films and the possible intrusion of government into the film making arena. It was time for a real solution.

Within weeks, discussions of Valenti's plan for a movie rating system began with the president of the National Association of Theatre Owners (NATO) and with the International Film Importers & Distributors of America (IFIDA), an assembly of independent producers and distributors. Over time, many meetings were held, including other guilds with actors, writers, directors and producers, as well as craft unions, religious organizations, critics and the heads of MPAA member companies.

NATO then acknowledged the objective of creating a new and revolutionary approach to rating movies. The initial design called for four rating categories including G for General Audiences, all ages admitted; M for mature audiences - parental guidance suggested, but all ages admitted; R for Restricted, children under 16 would not be admitted without an accompanying parent or adult guardian, which was later raised to under 17 years of age; and X rated, meaning that no one under 17 could be admitted.

Modifications happened when everyone realized the M category for "Mature" was regarded by most parents as a sterner rating than the R category. This was changed from M to GP (meaning General audiences, Parental guidance suggested). The next year this became its current label, "PG: Parental Guidance Suggested." By 1984, the PG category was split into two groupings, PG and PG-13, which meant a higher level of intensity than a film rated only PG. And by the year 1990, they included brief explanations of why a particular film received its R rating.

In summary, the initial mission of the movie review and rating system, which still exists, was to offer to parents some advance information about movies, so they can decide what movies they want their children to see or not to see.