Relationships (Outline)
Types Genetic or adoptive Kinship Family Stepfamily Parent Father Mother Son Daughter Grandparent Sibling Brother Sister Cousin Aunt Uncle Niece and nephew By marriage Spouse Husband Wife Open marriage Polygamy Polyandry Polygyny Group marriage Mixed-orientation Partner(s) Significant other Boyfriend Girlfriend Cohabitation Long-distance Online Same-sex Queerplatonic Friendship (romantic / cross-sex / zone) Intimate and sexual Casual Monogamy Non-monogamy Mutual monogamy Polyamory Polyfidelity Affair Cicisbeo Concubinage Courtesan Mistress
Activities Bonding Courtship Dating Engagement Bachelor's Day Mating Meet market Romance Singles event Wedding
Endings Breakup Legal/marital separation Annulment Divorce Widowhood
Emotions and feelings Affinity Attachment Intimacy Jealousy Limerence Love Platonic Unconditional Passion Sexuality
Practices Bride price dower dowry service Hypergamy Infidelity Sexual activity Transgression Repression
Abuse Child Dating Domestic Elderly Narcissistic parent Controlling behavior Stalking
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Casual sex is sexual activity that takes place outside a romantic relationship and implies an absence of commitment, emotional attachment, or familiarity between sexual partners.^[1][2] Examples are sexual activity while casually dating, one-night stands, prostitution or swinging and friends with benefits relationships.

A one-night stand is a single sexual encounter between individuals, where at least one of the parties has no immediate intention or expectation of establishing a longer-term sexual or romantic relationship. Anonymous sex is a form of one-night stand or casual sex between people who have very little or no history with each other, often engaging in sexual activity on the same day of their meeting and usually never seeing each other again afterwards.^[3]

The terms friends with benefits and booty call^[4] describe situations in which a person has sex with someone they generally consider a friend or someone they are fairly close to. They are not in an exclusive romantic relationship.^[5] The involved parties may have a degree of emotional attachment but do not want, for whatever reason, to have "strings attached".^[6]

A 2011 study, published in The Journal of Sex Research, found that two out of five single women and one out of five single men in "friends with benefits" relationships hoped that their relationship would eventually turn into a full-fledged romance.^[7] This stands in contrast to swinger couples who are already in long-term relationships and are only seeking compatible friends with whom they can engage in recreational sex.

Recreational sex can take place in an open marriage,^[8] among swingers (where sex is viewed as a social occasion),^[9][10] or in an open relationship.

A "hookup" (colloquial American English) is a casual sexual encounter involving physical pleasure without necessarily including emotional bonding or long-term commitment. It can range from kissing (for example, making out) to other sexual activities. The practice of hooking up became a widespread among young people in the 1980s and 1990s. Researchers say that what differentiates hooking up from casual sex in previous generations of young people is the "virtual disappearance" of dating, which had been dominant from the postwar period onwards. In more modern times, rather than dating, casual sex is the primary path for young people into a relationship.^[11] With the use of apps becoming more common it has become easier to hook up or meet others for sexual activity.^[12]

With students, studies have shown that the group most likely to engage in casual sex is white middle- or upper-class heterosexuals. Black and Latino students are less likely to hook up, as are evangelical Christian students and working-class students. Data on gay and lesbian students show mixed results, as some research shows that they engage in hookups at the same rate as heterosexual students, while others suggest that it occurs less frequently because college parties are not always gay-friendly, as most hookups occur at such gatherings.^[13][11]

A study of hookup culture at the University of Iowa found that waiting to have sex does not contribute to a stronger future relationship. Instead, what mattered most was the goal individuals had going into a relationship. Individuals who started by hooking up tended to develop a full relationship later if that was their goal going in.^[14] Another survey revealed that the number of first dates that most college-aged students have been on is about half of the number of hookups that they have had.^[15] It has become a common dating practice for people to candidly talk about their casual sex encounters and personal views on the subject as early as the first date or meeting.^[16] Another study showed that condoms were used in only 69 out of every 100 penetrative sex hookups.^[17]

Swingers engage in casual sex with others for a variety of reasons. For many, an advantage is the increased quality, quantity and frequency of sex.^[18] Some swingers engage in casual sex to add variety to their otherwise conventional sex lives or for curiosity. Swingers who engage in casual sex maintain that sex among swingers is often more deliberative and therefore more honest than infidelity. Some couples see swinging as a healthy outlet and a means to strengthen their relationship. Others regard such activities as merely social and recreational interaction with others.^[19] A swinger party or partner-swapping party is a gathering at which individuals or couples in a committed relationship can engage in sexual activities with others as a recreational or social activity.^[9] Swinging can take place in various contexts, ranging from a spontaneous sexual activity at an informal social gathering of friends to a regular social gathering in a sex club (or swinger club), private residence, or other pre-arranged location such as a hotel, a resort, or a cruise ship.^[20]

As automobile ownership boomed along with the number of options for dating venues, such as movie theaters and jazz halls, parental involvement in the courtship process began to decrease. Casual encounters became a more common occurrence in the teen and young adult dating experience.^[21]

Religious and moralist views from the preceding decades also led to public outcry in communities and in the press, and a questioning of what was perceived as changing standards in morality among the younger generation.^[22]

Some historians suggest that sexual liberation in the 1920s was largely the product of cultural changes and evolving gender roles. More young women sought to enter college and the workplace; many left parental homes and bad marriages behind and sought independence. The automobile was more of a new, convenient means to enable coupling than a causal phenomenon.^[23]

Also, young adults of the 1920s considered Victorian-era sexual and moral codes to be oppressive;^{[citation needed]} Bohemianism continued to influence and be embraced by this generation following WWI, and the liberated flapper and vamp emerged as lifestyle personas in popular culture. In the United States, "petting parties", in which petting ("making out" or foreplay) was the main attraction, became a part of the flapper lifestyle.^[24]

The emerging movie industry, through the Pre-Code Hollywood era, furthered the rebellion against Victorian-era morals as films started depicting women owning their sexuality. Current cinema from the 1960s onward has continued this trend.^[25]

During the sexual revolution in the United States and Europe during the 1960s and 1970s, social attitudes to sexual issues underwent considerable changes. The advent of "the pill" and other forms of birth control, the Women's Liberation movement, and the legalization of abortion in many countries are believed to have led to a wider practice of casual sex.^[26][27][28] That is also due in part to the younger generation's rejection of their parents' dating and matrimonial ideals and the rise of college party culture.^[29] In response to that insurgence in the 1960s, single women were denied access to birth control pills by their healthcare providers.^[30] That type of pushback is consistently observed throughout studies of the evolution of American sexual morals and beliefs. Younger generations are encouraged by their elders to engage in sexual activity only if it is within the bounds of marriage and for procreative purposes.^[16]

In the United States, one-time sexual encounters among college-aged students are growing increasingly common; nearly 70% of people in that age group have partaken in casual sex at least once because of their newfound adult identities and freedom to explore their sexualities.^[16][31]

Data from 2007 to 2017 indicates that there has been a decline in casual sex among young adults. A 2021 study attributed the decline to reduced alcohol consumption, increased video gaming, and a larger share of young adults living with their parents.^[32]

A study in 2019 found that 23% to 33% of women surveyed dated men for a free meal termed "foodie call".^[33]

Research suggests that as many as two thirds to three quarters of American students have casual sex at least once during college.^[34][13] On college campuses, casual sex may occur almost anywhere. The majority of hookups happen at parties. Other common casual sex venues are dorms, frat houses, bars, dance clubs, cars, and public places or wherever is available at the time.^[35]

Collegiate holidays and vacations, especially spring breaks, are times that undergraduates are more likely to purposely seek out casual sexual encounters and experiment with risky behaviors.^[36] This is due to the availability of alcohol and uninhibitedness of spring break venues.^[16] One study reported that about 30% of collegiate spring breakers, whether they are in a monogamous relationship or not, have penetrative sex with a person they meet during their break.^[37] A 1995 study of Canadian students who had traveled to Florida for spring break, found the key elements of a spring break vacation to include a group holiday with friends traveling and rooming together, a perpetual party atmosphere, high alcohol consumption, sexually suggestive contests and displays, and the perception that casual sex is common. Overall, there was a perception that sexual norms are far more permissive on spring break vacation than at home, providing an atmosphere of greater sexual freedom and the opportunity for engaging in new sexual experiences. Of the 681 students who completed a questionnaire after the break, 15% of males and 13% of females had engaged in casual sex during the break. Nearly 61% of men and 34% of women who had casual sex over the break had slept together within 24 hours of meeting.^[38]

Men and women are found to engage in very similar casual sex conducts, despite popular social beliefs. Most young adults in this age group believe that their peers are having a higher frequency of casual sex than they actually are, and this is due to vocabulary choice. For example, using the term "hookup" denotes that the sexual activity, whether it is vaginal sex, oral sex, or manual sex, is casual and between unfamiliar partners.^[16][39] However, it is vague and does not detail what specific sexual activities occurred. This is especially distorting towards others' impressions because 98% of college hookups involve kissing, 81% of hookups involve more than kissing, and only 34% of hookups involve penetrative sex.^[16][17][40] Studies have also linked this common misperception of peer hookup activity to media and pop culture portrayals of casual sexual encounters.^[16] Television and movies project distorted depictions of casual sex because they also commonly portray people who have just hooked up as emotionally satisfied and physically pleasured while simultaneously emotionally detached, which is not always the case.^[41] According to a 2004 peer-reviewed study published in the Journal of Marriage and Family found that women who have more than one premarital sexual relationship have a higher likelihood in the long run of disruptions if ever married, with this effect being the "strongest for women who have multiple premarital coresidential unions".^[42] Kahn and London (1991) found that premarital sex and divorce are positively correlated.^[43]

Attitudes to casual sex range from conservative and religious views, the extreme of which may result in imprisonment or even capital punishment for sexual relations outside heterosexual marriage, to liberal (libertarian or libertine) views, the extreme of which is free love.^[44]

The legality of adultery and prostitution varies around the world. In some countries there are laws which prohibit or restrict casual sex.

In some Muslim-majority countries, such as Saudi Arabia, Pakistan,^[45] Afghanistan,^[46][47] Iran,^[47] Kuwait,^[48] Malaysia, Morocco,^[49] Oman,^[50] Mauritania,^[51] United Arab Emirates,^[52][53] Sudan,^[54] and Yemen,^[55] any form of sexual activity outside marriage is illegal.

Many religions disapprove of sex outside marriage (see religion and sexuality), and the consequences range from very serious to none. Also, marriage is defined in quite different ways in different cultures, for example, with "short-term marriage" (see Nikah mut'ah).

Although some religious views look upon casual sex negatively,^[56] individual views on casual sex vary based on personal traits such as autonomy.^[57] Religious people and non-religious people mostly have similar feelings when it comes to having casual sex, with a bigger difference in attitude taking place between men and women.^[58]

Many specialist online dating services or other websites, known as "adult personals" or "adult matching" sites, cater to people looking for a purely sexual relationship without emotional attachments.^{[citation needed]} These can provide a relatively anonymous forum where people who are geographically close but in totally separate work and social circles can make contact.

Tinder is a free smartphone dating app that boasts over 10 million daily users, making it the most popular dating app for iOS and Android.^[59] In this app, users can either swipe right (which indicates interest) or swipe left (which indicates disinterest) on other users in hopes of matching each other. If both users swipe right on one another, they are a match, and messaging can be initiated between parties. This app is used for a variety of reasons, one of which is casual hookups. Men are more likely than women to use Tinder to seek out casual sexual encounters.^[60] This is attributed to men, in comparison to women, placing sexual pleasure at a higher level of importance and using social networking sites to fulfill this need.^[61] However, overall, more users are motivated to use it to find romance rather than sex. Despite this, there is a social concern as some believe that the app encourages hookups between users.^[60]

• Back-up partner
• Cottaging
• Dogging
• Fornication
• Friends with benefits relationships
• Group sex
• Open relationship
• Promiscuity
• Sociosexual orientation
• Treating (dating)

• Ehrenreich, Barbara, Elizabeth Hess, and Gloria Jacobs. Re-Making Love: The Feminization of Sex. Doubleday, 1986 (ISBN 0-385-18498-0)