Sex and religion. Since both sex and reproduction are fundamental in human and other life, it is not surprising that religions give central importance to both (the two are not synonymous, as will be seen). At the most basic level, religions have been in the past, and to a great extent still aspire to be, systems which protect gene replication and the nurture of children. It was not possible in the past to have any knowledge of genetics, but that, from an evolutionary point of view, is irrelevant. Natural selection operates on the heritable differences which occur between individuals whether those individuals are aware of it or not. The evolution of sex has therefore carried with it a vast range of different strategies through which the chances of successful reproduction are maximized (e.g. a mating pair might produce the maximum offspring in the minimum time with no nurture, so that a few individuals survive, e.g. herrings; or they might produce few offspring with long gestation and maximum nurture so that the few individuals survive, e.g. elephants—or humans). There is no suggestion that organisms make conscious decisions about the strategies they adopt; rather, the strategies adopted are winnowed impersonally by the test of whether they produce fit individuals to continue the process.

In the human case, however, consciousness is introduced. Thus although humans are carried by the same process of natural selection, they can also enhance the process by the creation of cultural defences and controls. It is in this sense that gene replication in the human case is protected by both the body and culture.

It is here that religions have been so important: they are the earliest cultural creations of which we have evidence which supply contexts of security and controls over human behaviours and evaluations of them. Sexual variance may thus be harnessed—or prohibited (e.g. celibacy or homosexuality may serve the community, or they may be regarded as aberrant): as always, religions produce a bewildering variety of different strategies. The resulting religious control has produced high degrees of stability: it has produced moral codes, designations of who may mate with whom (including prohibited relationships), techniques and rituals for producing offspring (often of a desired gender), education, protection of women, assurance of paternity (by restricting access to women) and thus of heredity and continuity in society. The consequence has been strong male control of women, in which have been combined reverence for women and subordination of them (see further WOMEN).

At the same time, religions have made much, in different ways, of the distinction between sex and reproduction. Even before the relation between sexual acts and reproduction was better understood, the potential of sex for pleasure and power was well-recognized. This, in itself, reinforced the male control of women, since promiscuous or unlicensed sexual activity would clearly subvert that ordering of families in particular and of society in general which was rewarded in natural selection. Within that context of restriction, the nature of sexuality and sexual feelings have evoked widely differing responses in religions, ranging from a fear of being enslaved to the passions (leading to a dualistic subordination of sexuality, as in Manichaeism) to a delight in sexuality as a proper end in life, as among Hindus: see puruṣārtha, kāma. In any case, the exploration of sexuality has been religiously important. In Eastern religions, in particular, the nature of sexual energy was explored in many directions. Since sexual arousal seems to make its own demands, what might be the consequence if that energy is brought under human control? In China this lent itself to the quest for immortality and the gaining of strength (see e.g. breath, ch'i, fang-chung shu, hsien, Taoism), in India to the acquisition of power (see Cakra Pūjā, Dūtī Pūjā, kālacakra, Kāpālika, maithuna, pañca-makāra, Sahajīyā, Śaktism, Tantrika, Tantrism). In Christianity, the issue of control led in a different direction. In so far as human sex transcends both reproduction and biological imperatives, it is no longer an end of that kind in itself. How, then, does it relate to the end of salvation and the vision of God? One answer is to say, Extremely well: the union of a man and a woman, transcending the union of male and female in a biological sense, has seemed religiously to be the nearest one can come on earth to the final union with God. But another answer has been to say that sex is of lesser value than the final end of God, and is among those things which may have to be given up if the unqualified love of God is to flourish. This ascetic option gives the highest value to celibacy, chastity, and virginity, and it became the dominant voice of the official Church, especially in the West. Male resistance to the erosion of male control has produced in all religions vigorous defences of the status quo, along with a deriding, as ‘political correctness’, of attempts to implement the recognition that women are no longer at the disposal of men. The Vatican resistance to the courtesy of gender-inclusive language is an obvious example of this. Contraception (see BIRTH AND POPULATION CONTROL) has been known to all religions and has been differently evaluated, but in general it has always been linked to the priority of reproduction, especially of male children who will continue the line of descent. In the last century, the development of simpler and more effective contraception has broken the link: sex and reproduction are no longer synonymous. The problems this is causing for male-dominated religious systems, intent on preserving the status quo, are great.