An adult movie theater is a movie theater designed only for adults to watch.Films and patronsAdult movie theaters show pornographic films primarily for either a respectively heterosexual or homosexual audience. For the patrons, rules are generally less strict regarding partial- or full-nudity and public masturbation or sex, and such behavior may be condoned explicitly or otherwise by the management. Such behavior may or may not be legal, and if not, may or may not be overlooked by local law enforcement. Certain theaters may also include a strip- or sex-show between films, or other sex industry services.Before the VCR and, later, the Internet, a movie theater or cinema house was often the only location where people could see hardcore adult films. The spread of home videos has led to a drastic reduction in the number of adult theaters.By regionUnited StatesThe earliest adult theaters in the U.S. were in California, and showed 35mm low production quality independently produced films. In 1960 there existed about 20 theaters in the USA that showed adult movies exclusively. In the late 1960s and early 1970s they spread to the rest of the country. Small "storefront" theaters with only a few dozen seats sprang up, and by 1970, 750 porn theaters existed in the U.S. In the 1970s, theaters shifted from showing 35mm sexploitation films to more explicit 16mm "beaver" films. In the 1980s, some theater owners began forming chains to cut their costs, and, by 1989, the number of U.S porn theaters had fallen below 250.