Anal sex

• 1. Introduction

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  Anal sex is a sexual practice that has been recorded across human history, from ancient Sumer to modern surveys, yet it remains one of the most contested and least openly discussed forms of sexual activity. Who engages in it, how widely, at what risk, and with what cultural meaning? Those questions sit at the center of this documentary.

  The practice encompasses far more than penile-anal penetration. Fingering, the use of toys like dildos and butt plugs, anilingus, and pegging all belong under the same heading. And the people who engage in it span every sexual orientation. Research consistently shows that anal sex occurs in heterosexual, homosexual, and lesbian relationships alike, though rates and contexts differ sharply across those groups.

  Health authorities including the World Health Organization flag unprotected anal sex as the riskiest form of sexual activity in terms of infection transmission. Yet cultural attitudes range from legal execution in some countries to quiet acceptance or outright celebration in others. That range of responses tells us as much about human societies as it does about the act itself. To understand why, we need to start with the body.

• 2. Anatomy and Sensation

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  The anal region is dense with nerve endings. The internal and external sphincter muscles that control the opening and closing of the anus are sensitive membranes composed of many nerve endings, capable of registering both pleasure and pain depending on circumstances. Human Sexuality: An Encyclopedia notes that "the inner third of the anal canal is less sensitive to touch than the outer two-thirds, but is more sensitive to pressure" and that "the rectum is a curved tube about 8 or 9 in long and has the capacity, like the anus, to expand."

  For men who receive anal penetration, the prostate sits adjacent to the rectum and can be stimulated indirectly through the anal wall. That stimulation can produce an orgasm described by some men as more widespread, more intense, and longer-lasting than what penile stimulation alone provides. The prostate is the larger male equivalent of the female Skene's glands. It is also common for men not to reach orgasm solely from anal sex in the receptive role.

  For women, the pathway to pleasure is more indirect. General statistics place the proportion of women who require direct clitoral stimulation to orgasm at 70-80%. Anal penetration can reach the clitoris indirectly through shared sensory nerves, particularly the pudendal nerve, which divides into the perineal nerve and the dorsal nerve of the clitoris. The clitoral crura, the internal legs of the clitoris, flank the vagina on each side and become engorged with blood when aroused, making them reachable via the nearby structures. Still, a woman reaching orgasm through anal stimulation alone is rare.

  Pornography has skewed public understanding of the anatomy here. It commonly portrays anal sex as painless and requiring no lubrication, which researchers say is inaccurate. The anal sphincter tissues tear more readily than vaginal tissue, and neither the anus nor the rectum produces natural lubrication. Researchers identify adequate personal lubricant, relaxation, and open communication between partners as the factors that prevent pain and tissue damage.

• 3. Who Engages, and How Often

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  Kimberly R. McBride's 2010 clinical review on heterosexual anal intercourse drew on a sample of 1,299 men and 1,919 women. It found that 51% of men and 43% of women had participated in at least one act of oral-anal sex, manual-anal sex, or anal sex toy use. Among those who reported heterosexual anal intercourse in the past year, 69% of men and 73% of women were in exclusive, monogamous relationships.

  A 2010 study from the National Survey of Sexual Health and Behavior, authored by Debby Herbenick and colleagues, found that 13% to 15% of men aged 25 to 49 had practiced insertive anal intercourse. Partnered women between ages 18 and 49 were significantly more likely to report anal sex in the past 90 days than women outside those age brackets, though women reported it less commonly than men overall.

  Among men who have sex with men, the picture differs from the popular association. Research published in the Journal of Sexual Medicine in 2011 found that in the most recent sexual encounter between homosexual men, kissing on the mouth was the most common behavior, followed by oral sex and mutual masturbation. Anal sex occurred in fewer than half of those sexual encounters. A survey published by The Advocate in 1994 found that among homosexual men who do have anal sex, 46% preferred the insertive role and 43% preferred the receptive role. A 2012 National Survey of Sexual Health and Behavior study found that among homosexual men who engage in anal sex, 83.3% reported ever having been in the insertive position and 90% in the receptive position.

  Research into lesbian sexual practices is thinner. A non-scientific 1987 study of more than 100 members of a Colorado lesbian social organization found that women in their 30s were twice as likely as other age groups to engage in anal stimulation. A 2014 study of partnered lesbian women in Canada and the U.S. found that 7% engaged in anal stimulation or penetration at least once a week, roughly 10% did so monthly, and 70% did not at all.

  A 2000 study found that 22.9% of college students who identified as non-virgins had engaged in anal sex. Those students used condoms during anal sex only 20.9% of the time, compared with 42.9% of the time during vaginal intercourse. Researchers have linked rising rates of heterosexual anal sex in part to increased consumption of anal pornography, particularly among men who view it regularly.

• 4. Health Risks and Physical Consequences

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  Unprotected receptive anal sex with an HIV-positive partner is the single sex act most likely to result in HIV transmission. That finding from health authorities places it at the top of the risk hierarchy for sexually transmitted infections. The anal sphincter is a delicate tissue that tears readily; those tears create direct entry points for pathogens. The World Health Organization recommends condom use and safer sex practices for all anal sex.

  Condoms themselves carry a higher failure rate during anal sex than during vaginal sex because the tightness of the anal sphincters creates more friction during the act. A condom can break or slip off under those conditions more easily than in other forms of sex.

  The American Cancer Society estimated that in 2023, approximately 9,760 new cases of anal cancer were diagnosed in the United States, with roughly 6,580 in women and 3,180 in men, and that approximately 1,870 deaths resulted. Most anal cancer cases are linked to infection with the human papillomavirus (HPV), which is often transmitted through unprotected anal sex. The average age at diagnosis is in the early 60s, and the disease affects women somewhat more often than men.

  Pain during receptive anal sex has a clinical name: anodyspareunia. Two population studies of men receiving anal sex found that 18% and 14% reported it. In a study of 2,002 women, 8.7% of those who had engaged in anal sex reported severe pain. Researchers have identified psychological factors as primary contributors to that pain in some cases, and communication between partners as a meaningful preventive measure.

  Physical damage can also extend beyond pain. Anal sex can worsen existing hemorrhoids or cause new ones to form. Tiny tears in the rectal mucous membrane and minor bleeding are common results of penetrative anal sex because the mucous membrane is thin and small blood vessels lie directly beneath it. More serious outcomes include anal fissures and, in rare cases, perforation of the colon, which requires immediate medical attention. Anal fisting carries a particularly elevated risk of sphincter laceration and rectosigmoid perforation, which can be fatal. Repetitive penetrative anal sex may weaken the anal sphincters over time, potentially leading to fecal incontinence or rectal prolapse, though the latter is described as very uncommon and its causes are not well understood. Kegel exercises have been used as a counter-measure to strengthen the pelvic floor.

• 5. Ancient Worlds, Varied Codes

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  The ancient Sumerians left some of the earliest recorded attitudes toward anal sex, and those attitudes were notably relaxed. Entu priestesses, forbidden from producing offspring, engaged in anal sex as a method of birth control. A Sumerian text describes an omen in which a man urges his wife to "Bring your backside." The gala, priests who served the goddess Inanna and performed elegies in her temples, were recorded as having homosexual inclinations; the Sumerian sign for gala was a ligature of the signs for "penis" and "anus." One surviving Sumerian proverb reads: "When the gala wiped off his ass he said, 'I must not arouse that which belongs to my mistress i.e., Inanna.'"

  In ancient Greece, the picture was more complicated. The playwright Aristophanes mockingly claimed, "Most citizens are europroktoi ('wide-arsed') now." Greek residents used terms including kinaidos, europroktoi, and katapygon to categorize men who chronically practiced passive anal intercourse. Pederastic relationships in Athens and Sparta were expected to avoid penetrative sex entirely; Greek artwork more commonly depicted fondling or intercrural sex between men and boys, and some sources explicitly describe male-male anal intercourse as shameful and a form of hubris. By contrast, in later Roman-era Greek poetry, anal sex with youths of "eligible" age became a literary convention.

  Rome mapped a different set of rules onto the same acts. A free male citizen taking the receptive role in anal intercourse was condemned as impudicitia, meaning immodesty or lack of chastity. Free men could take the active role with young male slaves known as catamites or pueri delicati. The same logic applied to women: a man performing anal sex on a woman was described as having her "take the boy's role." Roman comedies and plays used Greek settings when depicting explicit anal intercourse, which may reflect a Roman tendency to think of the practice as specifically Greek.

  Far from the Mediterranean, the Moche people of Peru left erotic pottery that researchers have studied in detail. In one survey of a collection of Moche stirrup-spout pots, 31% depicted male-female anal intercourse more than any other sex act. That pottery belonged to the world of the dead, where common practices were believed to be reversed. The Larco Museum in Peru houses an erotic gallery displaying this pottery. In precolonial Papua New Guinea, the Kaluli people hosted ceremonies called bau a every several years, in which older men engaged in anal intercourse with boys and younger men in a darkened room. The Kaluli believed the practice improved boys' growth and maturity.

• 6. Religion, Law, and Prohibition

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  The Mishneh Torah, considered authoritative by Orthodox Jewish sects, permits anal sex between a husband and wife provided that semen is not expelled purposelessly, though it frames such activity as something a pious man should approach with seriousness rather than levity.

  Christian tradition developed several formal condemnations. Anal sex is referred to in Christian texts as the peccatum contra naturam, meaning "the sin against nature" after Thomas Aquinas, or as Sodomitica luxuria, "sodomitical lusts," a phrase that appears in one of Charlemagne's ordinances. A third formulation, peccatum illud horribile, inter christianos non nominandum, translates roughly as "that horrible sin that among Christians is not to be named."

  In Islam, the concept of liwat, associated with the sin of Lot's people, is officially prohibited by most Islamic sects. References in the Quran to the destruction of Sodom and Gomorrah are interpreted as condemnation of "unnatural" sex. Men who practice same-sex anal intercourse are called luti or lutiyin in plural and are classified as criminals under some Islamic legal systems.

  The legal consequences can still be lethal. Iran's Penal Code states in Article 109 that "both men involved in same-sex penetrative (anal) or non-penetrative sex will be punished." Article 110 states that those convicted of engaging in anal sex will be executed, with the manner of execution left to the judge's discretion. Historically, in some societies, individuals discovered to have engaged in anal sex between males were put to death by decapitation, burning, or mutilation.

  In the United States, one study found that teenagers who pledged not to have sex until marriage were more likely than non-pledging teens to engage in anal sex without vaginal sex. Those pledge-takers were just as likely as non-pledgers to test positive for a sexually transmitted infection five years after taking the pledge. Some Christian communities in the U.S. have also been documented using anal sex as a means of preserving what they consider female virginity, a practice sometimes called technical virginity, because it does not result in pregnancy and does not rupture the hymen.