Human sexuality

Lore & Background

Sexuality involves biological and physical aspects largely concerning human reproductive functions, including the human sexual response cycle. Interest in sexual activity normally increases when an individual reaches puberty. The biological aspects deal with the reproductive system, the sexual response cycle, and factors affecting these, as well as organic and neurological responses, heredity, hormonal issues, gender issues, and sexual dysfunction.

Reader's Guide

The study of human sexuality is significant because it integrates biological, psychological, and sociocultural dimensions, affecting and being affected by cultural, political, legal, philosophical, moral, ethical, and religious aspects of life. Evidence regarding sexual orientation leans considerably more toward non-social causes than social ones, especially for males, with cross-cultural evidence showing that tolerance of homosexuality does not significantly increase its incidence. Gender differences in sexuality are observed in attitudes toward casual sex, with men generally more approving, but other aspects such as sexual satisfaction and attitudes toward homosexuality show little difference. The hypothalamus is the most important brain region for sexual functioning, and hormones such as oxytocin, prolactin, follicle-stimulating hormone, and luteinizing hormone play key roles in reproduction and bonding.

Did You Know?

• Oxytocin, sometimes called the 'love hormone,' is released in both sexes during sexual intercourse when an orgasm is achieved.
• The hypothalamus is the most important part of the brain for sexual functioning.
• Cross-cultural evidence shows that cultures very tolerant of homosexuality do not have significantly higher rates of it.
• Hypothesized social causes of sexual orientation are supported by only weak evidence, distorted by numerous confounding factors.

Philosophical Foundations and the Evolutionary Turn

Though his analysis drew almost entirely from close readings of ancient mythology, Bachofen's framework captivated later thinkers including Lewis Henry Morgan and Friedrich Engels, who both engaged critically with his ideas. Today, the dominant explanatory model has shifted away from such mythological narratives toward evolutionary biology and human behavioral ecology. Under this lens, the human genotype reflects the reproductive success of ancestors who left more offspring, not any conscious individual strategy to maximize reproduction. Natural selection does not anticipate the future; rather, present-day sexual behaviors are best understood as the residue of selective pressures operating during the Pleistocene epoch, long before written records existed.

Two-Spirit Traditions and Colonial Erosion

Among the vast diversity of Indigenous tribes, cross-gender roles known historically as berdache existed in pre-colonial communities including the Kaska of the Yukon Territory, the Klamath of southern Oregon, and the Mohave, Cocopa, and Maricopa peoples along the Colorado River. These individuals adopted the traditional roles, mannerisms, and labor of the opposite sex. In Mohave ceremony, cross-gender females could be ritually transformed into males, granting them the right to marry women. For most Native Americans, a person's spirit held greater significance than their physical body, and those who crossed gender boundaries were understood as inhabiting a third category distinct from both male and female. Two-spirit individuals frequently entered same-sex relationships, fulfilling family-unit duties expected in Native societies, yet two-spirit persons of the same sex did not marry each other because marital roles mattered more than sexuality itself. This tradition eroded in the late nineteenth century under the pressure of white settlers who imposed their own sexual values, declaring female gender inferior and homosexuality unnatural.

India's Pioneering Sexual Philosophy and Literature

India occupies a distinctive place in the global history of sexuality, having produced some of the earliest written treatises that approached sexual intercourse as a systematic discipline. The ancient Vedic texts of Hinduism, Buddhism, and Jainism reveal moral frameworks surrounding sex, marriage, and fertility. One striking example is the Asvamedha Yajna ritual, which culminated in the chief queen lying with a dead horse in a simulated sexual act—a fertility rite designed to protect and enhance the kingdom's productivity and martial strength. The great epics Ramayana and Mahabharata reinforced the notion that sex was a mutual obligation between married partners, and their influence radiated across Chinese, Japanese, Tibetan, and Southeast Asian cultures. The Kama Sutra, perhaps India's most widely recognized sexual text, was composed for and preserved by philosopher, warrior, and noble castes along with their servants, concubines, and certain religious orders—essentially the literate and educated classes. India thus pioneered the use of sexual education through art and literature, though rulers often indulged in hedonistic lifestyles that did not reflect the moral attitudes of ordinary people.

The Scarcity of Reliable Historical Evidence

Constructing an accurate history of human sexuality is hampered by a fundamental problem: for most of recorded time, writing was accessible to only a small fraction of any society's population. The resulting self-censorship and reliance on euphemistic language mean that explicit, precise evidence is scarce. Sexual speech and writing have been governed by shifting standards of decorum since the earliest periods of history, further distorting the record. Scholars must therefore piece together understanding from a patchwork of primary sources spanning many eras and cultures. These include legislative records that either encourage or prohibit certain behaviors, religious and philosophical texts that recommend, condemn, or debate sexual topics, literary works—sometimes unpublished during the author's lifetime—such as diaries and personal correspondence, medical textbooks that classified various sexual forms as pathological conditions, and linguistic developments particularly in slang. More recently, empirical studies of sexuality have added another layer of evidence, though they represent only a tiny slice of the deep historical record that remains largely unwritten.