1960s
Credit: Wikipedia

In the late '60s (a time when Playboy was at its cultural height) there started to be some backlash against pornography and other sexually explicit materials. President Lyndon B. Johnson appointed a committee in 1968, called the Commission on Obscenity and Pornography, in order to study the relationship between obscene materials and anti-social behavior. By the committee's termination in 1970, they had found insufficient evidence to prove that sexual materials caused delinquent or criminal behavior. At this time, the sexual revolution was in full swing.