Marty Ralph Klein (born 1950) is an American sex therapist, author, educator and public policy analyst. Klein has spent his career supporting the healthy sexual expression of men, women and couples in a wide range of ways. He is critical of censorship, the concepts of sex addiction and porn addiction, as well as the anti-pornography movement. He believes that public policy relating to sexuality should be driven by scientific data rather than emotion, "tradition" or popular but untrue myths. He has been a participant in various state, federal and international court cases dealing with the First Amendment, obscenity, censorship and "harmful to minors" laws.
