By the late 1960s, the restrictive Hays Code—which banned things like interracial relationships and profanity—had become obsolete. In its place, MPAA president Jack Valenti introduced the voluntary film rating system on November 1, 1968. Initially, there were four ratings: G (General Audiences), M (Mature Audiences, later changed to GP, then PG), R (Restricted), and X (Adults only). This shift allowed filmmakers to explore more adult themes without fear of government censorship, as the responsibility for content shifted to the parents. A major change occurred in 1984 after films like 'Indiana Jones and the Temple of Doom' and 'Gremlins' were criticized for being too violent for PG but not adult enough for R. This led to the creation of the PG-13 rating, which has since become the most common rating for major Hollywood blockbusters.