to avoid "the possible intrusion of government into the movie arena", he developed a set of advisory ratings which could be applied after a film was completed. On November 1, 1968, the voluntary MPAA film rating system took effect, with three organizations serving as its monitoring and guiding groups: the MPAA, the National Association of Theatre Owners (NATO), and the International Film Importers & Distributors of America (IFIDA). Only films that premiered in the United States after that date were affected by this. Walter Reade was the only one of 75 top U.S. exhibitors who refused to use the ratings. Warner Bros.-Seven Arts' The Girl on a Motorcycle was the first film to receive the X rating, and was distributed by their Claridge Pictures subsidiary. Two other films were rated X by the time the MPAA published their first weekly bulletin listing ratings: Paramount's Sin With a Stranger and Universal's Birds in Peru. Both films were subsequently released by subsidiaries. The ratings used from 1968 to 1970 were: Rated G: Suggested for general audiences. Rated M: Suggested for mature audiences - Parental discretion advised. Rated R: Restricted – Persons under 16 not admitted, unless accompanied by parent or adult guardian. Rated X: Persons under 16 not admitted. This content classification system originally was to have three ratings, with the intention of allowing parents to take their children to any film they chose. However, the National Association of Theatre Owners urged the creation of an adults-only category, fearful of possible legal problems in local jurisdictions. The "X" rating was not an MPAA trademark and would not receive the MPAA seal; any producer not submitting a film for MPAA rating could self-apply the "X" rating (or any other symbol or description that was not an MPAA trademark). From M to GP to PG In 1970, the ages for "R" and "X" were raised from 16 to 17. Also, due to confusion over whether "M"-rated films were suitable for children, "M" was renamed to "GP" (for General audiences, Parental guidance suggested), and in 1971, the MPAA added the content advisory "Some material not generally suitable for pre-teenagers". On February 11, 1972, "GP" was revised to "PG". The ratings used from 1970 to 1972 were: Rated G: All ages admitted – General audiences. Rated GP: All ages admitted – Parental guidance suggested. [Sometimes a disclaimer would say "This film contains material which may not