Sexual interest in and attraction to members of one's own sex. Female homosexuality is frequently referred to as lesbianism; the word gay is often used as an alternative for both homosexual and lesbian, though it may refer specifically to male homosexuality. At different times and in different cultures, homosexual behaviour has variously been encouraged, approved of, tolerated, punished, and banned. Homosexuality was not uncommon in ancient Greece and Rome, particularly between adult and adolescent males. Jewish, Christian, and Muslim cultures have generally viewed it as sinful, although many religious leaders have said it is the act, and not the inclination, that their faiths proscribe. Attitudes toward homosexuality are generally in flux, partly because of increased political activism (see gay rights movement). Until the early 1970s many medical organizations, such as the American Psychiatric Association, classified homosexuality as a mental illness, but that designation was widely dropped in subsequent years. Longstanding beliefs about homosexuals (including the stereotype that gay men are weak and effeminate and lesbians aggressive and masculine) have also largely faded; some countries, cultures, and religious groups, however, continue to view homosexuality as deviant. Homosexual orientation, like sexuality in general, apparently results from a combination of hereditary factors and social or environmental influences, and it tends to coexist with heterosexual feelings in varying degrees in different individuals.