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Sexual intercourse, also called coitus, or simply, to have sex is the human form of copulation. In humans this is performed relatively frequently and primarily for sexual pleasure rather than in response to a seasonal stimulus. Coitus may be preceded by foreplay, which leads to sexual arousal of the partners, resulting in the 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 their hips to move the penis backward and forward inside the vagina to cause friction, typically without fully removing the penis. In this way, they stimulate themselves and each other, often continuing until orgasm and ejaculation are achieved. Penetration by the hardened erect penis is also known as intromission, or by the Latin name immissio penis. Sexual reproduction Coitus is the basic reproductive method of humans. During ejaculation, which usually accompanies male orgasm, a series of muscular contractions delivers semen containing male gametes known as sperm cells or spermatozoa from the penis 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 then into the fallopian tubes. Millions of sperm are present in each ejaculation, to increase the chances of one fertilizing an egg or ovum. If female orgasm occurs during or after male ejaculation, the corresponding temporary reduction in the size of the vagina and the contractions of the uterus that occur can help the sperm to reach the fallopian tubes. 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. Heterosexual intercourse (coitus), where both participants are believed to be fertile, should always be considered likely to result in pregnancy, unless adequate contraceptive (birth control) measures are taken. Functions of sex beyond reproduction
Sexual drive The urge of adult humans to have sexual intercourse is seen as being part of the biological need for social bonds. It is categorized with the needs for family, friends, and group acceptance in Maslow's hierarchy of needs. Moreoever, it is a basic instinct for survival, by way of reproduction and extend bloodline. The very need for sexual intercourse may have more to do with reproduction then creating social bonds. At an emotional level sexual intercourse is often, though not always, seen as the ultimate physical expression of feelings of romantic love between two humans. In many cultures, mutual romantic love often forms a formalized or informal partnership, a full sexual relationship within this partnership, procreation or adoption of children, and subsequent parenting. On a biological level, an increasing amount of research is demonstrating that a man's sex drive (and sexual attractiveness to women) is closely linked with hormones such as testosterone. A man can boost his testosterone naturally through reducing (or eliminating) smoking, alcohol, certain drugs such as most anti-depressants, emotional stress, and simple carbohydrates such as white sugar. He should also avoid exposing his testicles to too much heat such as from a hot tub. Conversely, eating a diet of 70% fruits and vegetables and 25% to 30% protein boosts a man's testosterone, as does drinking more water, lifting weights, sunbathing, and meditation. Sexual intercourse is also often decoupled from romantic love and/or from a wish for procreation. Casual sex, often used to satisfy a physiological or psychological need, is common although it is censured by some as being promiscuous and morally questionable. The sex industry is the commercialization of sex, and includes the production of pornography, erotic art, and erotic literature, as well as prostitution. Sexual-intercourse difficulties While being well suited for effective stimulation of the penis, intercourse is less well suited for effective stimulation of the clitoris. Many women, up to 70 percent rarely or never orgasm during intercourse without simultaneous direct stimulation of the clitoris. Most women require direct clitoral stimulation in order to achieve orgasm. Disregard of this fact is seen as a common cause of female anorgasmia. Anorgasmia is the lack of orgasm during otherwise pleasurable stimulation. It is much more common in women than men. Usually, the condition is related to a psychological aversion to sexual pleasure, or to a basic lack of knowledge of what she finds physically pleasing. A sense of shame, or the feeling that she "should" be able to orgasm can compound the problem, as well as feelings of shame on the part of her partner, from the feeling that he cannot please her. Masturbation is one of the best ways for a woman to explore her body and discover what feels good for her. The absence of a partner can remove the sense of performance anxiety and allow the woman to relax and enjoy. Good communication and patience are essential in helping an anorgasmic woman achieve orgasm. Whether a woman considers anorgasmia a problem or not is highly individual, though many women find it very frustrating. Some males suffer from erectile dysfunction (ED), 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 because they are accompanied by serious risks such as increased chance of heart attack. Also, using a drug to counteract the symptom—impotence—can mask 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). The U.S. Food and Drug Administration (Food and Drug Administration) is 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 to 34 percent of men in the United States. The AUA also estimates that 10 to 12 percent of men in the United States are affected by erectile dysfunction. Vaginismus is involuntary tensing of the pelvic floor musculature, making coitus distressing or impossible. Dyspareunia is painful or uncomfortable intercourse which can be due to a variety of causes. Sexual ethics and legality Unlike some other sexual activities, sexual intercourse has rarely been made taboo on religious grounds or by government authorities, as procreation is inherently essential to the continuation to the species or of any particular genetic line, which is considered to be a positive factor, and indeed, enables most societies to continue in the first place. Many of the cultures that had prohibited sexual intercourse entirely no longer exist; an exception is the Shakers, a sect of Christianity that has very few adherents at current. There are, however, many communities within cultures that prohibit their members to engage in any form of sex, especially members of religious orders and the priesthood in the Roman Catholic Church and lamas in Buddhist monasteries. 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 culture for thousands of years. These have included prohibitions against specific positions, but even more often against: Some cultures and religions also prohibit or at one point prohibited sexual intercourse during a woman's menstrual period, such as Islam and Judaism, wherein the main sacred text laid specific instructions for behavior during and after this period, including explicitly forbidding sexual contact. Often a community adapts its legal definitions during case laws for settling disputes. For example, in 2003 the New Hampshire Supreme Court ruled that same-sex relations do not constitute sexual intercourse, based on a 1961 definition from Webster's Third New International Dictionary, in Blanchflower v. Blanchflower, and thereby an accused spouse in a divorce case was found not guilty of adultery based on this technicality. Most countries have age of consent laws specifying the minimum legal age for engaging in sexual intercourse. Sexual intercourse with a person against their will, or without their informed legal consent, is referred to as rape, and is considered a serious crime in many cultures around the world, including those found in Europe, northern and eastern Asia, and the Americas. A consequence of this is that it may be illegal to have sex with someone who is intoxicated, because that person cannot give their informed consent. Sex, regardless of consent, with a minor (a person under the age of consent) is often considered a comparable or equivalent crime to rape or sexual assault, especially in instances where the older partner is not also a minor. The age of consent varies from country to country and sometimes even within the same country; generally, the age of consent is set anywhere between thirteen and eighteen years of age. Religions For a broad overview, see Religion and sexuality. | |||||||||
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