Sexuality and the norms regulating it are regarded as strictly culture-specific and therefore sex-related standards vary from religion to religion. Sex has a dual role in society: on the one hand it is a reproduction mechanism, whilst on the other hand it is also be crucial for the most intimate of interpersonal relations. In Christianity sexuality has a practical role, which can be summed up in a quote from Genesis: "God blessed them and said: ‘Be fruitful and increase in number and fill the water in the seas and let the birds increase on the earth.'" (Genesis 1:22).
The interaction between religious beliefs and sexuality has caused many major debates over the years, with the three main monotheistic religions – Judaism, Christianity and Islam – favoring heterosexual monogamy. Some of the less conservative members of religious groups believe that homosexuality is not a sin but the practice of homosexual intercourse remains morally inappropriate and unacceptable.
Most religions attempt to regulate sexual behavior through their moral codes and often prescribe sexual conduct norms. A small number of religious movements encourage sexual conduct without any restrictions. Religious norms cover premarital sex, extramarital sex, divorce, masturbation, abortion, contraceptives and homosexuality. As religious norms about sexual morals were introduced in order to ensure the harmonious survival of the community, religions primarily forbid incest, promiscuity and adultery.
In the 13th century, the Roman Catholic Church recognized marriage between a baptized man and woman as a sacrament, accepting sex only for its procreation purposes and therefore viewing it as appropriate only within a marriage. The fact that celibacy is a major Christian virtue is illustrated in the instance of the immaculate conception of the Virgin Mary. In any other case, sexuality was mostly related to shame, temptation and inappropriateness. This attitude is derived primarily from the Original Sin doctrine, which also predetermines the stricter attitude and lower tolerance to female sexuality and sexual behavior. The Catholic Church remains strongly opposed to premarital sex, divorce, contraceptives and homosexuality. In some Catholic countries the ban on abortion remains an important and controversial issue.
Compared to Catholicism, Protestant churches in some cases accept or at least turn a blind eye to divorce, homosexuality, contraceptives or other forms of human sexual behavior that have by now become widespread amongst the countries affected by the waves of the sexual revolution of the 20th century. While Islam and Judaism can be strict in terms of everyday moral conduct, especially Orthodox Judaism and Shiite Islam, in terms of sexual morality they are sometimes surprisingly liberal. This is in contrast to the Catholic Church, which is much stricter on sexuality than on many other matters of everyday life. In Orthodox Judaism, sex is not considered to be sinful but is permissible only in the context of marriage. In addition, Leviticus, which is a major source of Jewish law, forbids sexual intercourse between males. Other more liberal branches of Judaism treat the sexes equally and some back gay civil partnerships.
Buddhism appears to be more tolerant on issues such as homosexuality and abortion. In Buddhism, most forms of sexuality are regarded as spiritual and therefore acceptable. Sex, as a symbol of fertility, can be incorporated in a religious ritual, particularly in Paganism. An example of this would be the Dionysian Mysteries, which were a ritual in Ancient Greece and Rome, involving ecstatic dances, heavy drinking and sexual activities.
Meanwhile, the issue of sexuality and religion is closely related to gender roles in society and the place of the woman in the community. After centuries of flagrant inequality, Christianity started to pay more attention to gender roles and gender rights. Hence, some Protestant churches accept women as priests. However, the woman in Islamic society generally still has a low-profile role. In many Islam countries for instance women are expected to wear a veil, thus hiding their sexuality from anybody except for their husband.