Sexual intercourse

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This article is about sexual intercourse in humans and its societal implications. For biological copulation in general, see copulation.
The missionary position is the most common position for sexual intercourse in humans
The missionary position is the most common position for sexual intercourse in humans
The cowgirl sex position is a position frequently combined with kissing, caressing, and embracing of the paramour
The cowgirl sex position is a position frequently combined with kissing, caressing, and embracing of the paramour


The Doggy position is thus named because canines, as well as most other mammals, use this position.
The Doggy position is thus named because canines, as well as most other mammals, use this position.

Sexual intercourse or coitus is the human form of copulation. In a wider context, the term sexual intercourse may refer to a wider range of sexual activities than the term coitus, which usually only refers to vaginal intercourse. See human sexual behavior for a discussion of the broader sense of sexual intercourse, and for information on the wide variety of sexual activities there are to choose from.

Sexual intercourse may be preceded by foreplay which leads to sexual arousal of the partners, resulting in erection of the penis and natural lubrication of the vagina. To engage in sexual intercourse, the erect penis is inserted into the vagina and one or both of the partners move back and forth to repeatedly pull the penis out (but usally not all the way out) and push it back in. In this way, they stimulate themselves and each other usually until they achieve orgasm and ejaculation. A detailed description of the physiology of sexual arousal and orgasm can be found in the article Human sexual response cycle.


Biology of conception

Coitus is the basic reproductive method of humans. During ejaculation, which normally accompanies male orgasm, a series of muscular contractions delivers semen containing male gametes known as sperm cells or spermatozoa into the vault of the vagina. The subsequent route of the sperm from the vault of the vagina, is through the cervix and into the uterus, and thence into the fallopian tubes. Millions of sperm are present in each ejaculation, to increase the chances of one fertilizing an egg or ovum. Sperm cells can survive up to nine days in the female body. When a fertile ovum from the female is present in the fallopian tubes, the male gamete joins with the ovum resulting in fertilization and the formation of a new embryo. When a fertilized ovum reaches the uterus, it becomes implanted in the lining of the uterus known as endometrium and a pregnancy begins.

Sexual intercourse should always be considered likely to result in pregnancy unless adequate contraceptive (birth control) measures are in force, or unless one (or both) of the partners is not fertile. For example a woman who has passed through the menopause cannot conceive, but can still participate in, and enjoy, intercourse. Where both participants are believed to be fertile pregnancy should still be considered as a possible outcome of intercourse since no birth control measure is 100% effective. Coitus interruptus, or withdrawal of the penis from the vagina just before the man's orgasm, cannot be considered an effective method of contraception and is not recommended, as the male usually releases a small amount of semen before the main ejaculation. If both partners are fertile, abstinence from heterosexual sexual intercourse or sterilization are the only 100% effective ways to avoid pregnancy. Outercourse, and other sexual contact (such as mutual masturbation or oral sex), in which there is sexual activity without penis insertion, can be performed without resulting in pregnancy provided that semen does not come in contact with the vulva.

Problems of intercourse

Some males suffer from erectile dysfunction, or impotence, at least occasionally. For those whose impotence is caused by medical conditions, prescription drugs such as Viagra, Cialis, and Levitra are available. However, doctors caution against the unnecessary use of these drugs since they are accompanied by serious risks such as increased chance of heart attack. Also, as is too often the case, using a drug to counteract the symptom, impotence, masks the underlying problem causing the impotence, and does not fix the problem. A serious condition might be aggravated if left untreated.

A more common sexual disorder in males is premature ejaculation (PE). Those afflicted with PE can perform intercourse for an average of 1.8 minutes before experiencing an orgasm. This compares with an average of 7.3 minutes for those not suffering from premature ejaculation. The U.S. Food and Drug Administration (FDA) is currently examining the drug dapoxetine to treat premature ejaculation. In clinical trials those with PE who took dapoxetine experienced intercourse three to four times longer before orgasm than without the drug.

The American Urological Association (AUA) estimates that premature ejaculation could affect 27 percent to 34 percent of men in the United States. The AUA also estimates that 10 percent to 12 percent of men in the United States are affected by erectile dysfunction.

Inability to achieve orgasm is called anorgasmia. It is much more common in women than men and usually needs attention from both partners over a long time span to solve. Many women, especially younger women with little sexual experience, have difficulty achieving orgasm. Whether a woman considers anorgasmia a problem or not is highly individual; the popular but dubious notion that both partners should achieve orgasm in "normal" intercourse may contribute to a woman's concern over anorgasmia.

Vaginismus is involuntary tensing of the pelvic floor musculature, making coitus distressing or impossible. Dyspareunia is painful or uncomfortable intercourse; it can be due to a variety of reasons.

Sexually transmitted diseases

Main article: sexually transmitted diseases

Sexual intercourse, like other sexual activities that involve the possibility of transfer of body fluids, is also a means of propagating sexually transmitted diseases (STD's). According to the Centers for Disease Control and Prevention, "The surest way to avoid transmission of sexually transmitted diseases is to abstain from sexual intercourse, or to be in a long-term mutually monogamous relationship with a partner who has been tested and you know is uninfected. For persons whose sexual behaviors place them at risk for STDs, correct and consistent use of the male latex condom can reduce the risk of STD transmission."[1]

Morality and legality

Various laws, moral rules, and taboos surround sexual intercourse. See sexual morality for a detailed discussion.

Unlike some other sexual activities, sexual intercourse itself has rarely been made taboo on religious grounds or by government authorities. It is believed that all of the cultures that prohibited sexual intercourse entirely no longer exist, save the Shakers, a sect of Christianity which has very few adherents, although there are many communities within cultures who prohibit their members to engage in any form of sex, mostly these are religous orders such as monks, priests, nuns, etc. Within some ideologies, coitus has been considered the only "acceptable" sexual activity. Relatively strict designations of "appropriate" and "inappropriate" sexual intercourse have been almost universal in human societies. These have included prohibitions against specific positions, against intercourse among partners who are not married (this is called fornication) or at least one of whom is married, but not to each other (called adultery), against sexual intercourse with a close relative (called incest), and against intercourse during a woman’s menstrual period.

Most countries have age of consent laws specifying the minimum legal age for engaging in sexual intercourse. Sexual intercourse with a person against his or her will, or without their informed legal consent, is called rape and is considered a serious crime in most cultures.

There is a good deal of controversy about the kind of relationship one should have with someone else before engaging in sexual intercourse. This controversy is beyond the scope of this article; interested readers are encouraged to read the articles on chastity, evolutionary psychology, and sexual morality.

Postures of the body during sexual intercourse

Main article: List of sex positions

Sexual intercourse may be performed in a wide variety of positions, the most common ones being:

  • The woman lying on her back, the man on top and facing her ("missionary position")
  • The woman on hands and knees, the man kneeling behind her ("doggy style" or in Latin coitus more ferarum "sex in the manner of beasts")
  • The man on his back or sitting, the woman kneeling or squatting on top (slang "cowgirl" if the woman faces the man or "reverse cowgirl" if the woman faces away from him)
  • Both partners lying on their sides, the man entering from the front ("side-by-side position")
  • Both partners lying on their sides, the man entering from behind ("spooning")


There is a mistaken belief that dolphins, bonobos, and humans are the only animals that are known to have sex strictly for the sake of pleasure. In actual fact, it is not possible to know what an animal is feeling when they engage in sexual intercourse. What distinguishes these three species from other animals is that they have heterosexual sex when the female is not at a point in her gestation cycle suitable for successful impregnation [2]. Extrapoliting from this observation has led to the conclusion that the animals are engaging in sexual intercourse for the sake of pleasure.

Another myth is that only humans have homosexual sex but Bonobos regularly engage in various forms of intercourse and/or stimulation of the same sex,in addition to other animals such as dogs.

See also

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