Incidence of monogamy

The incidence of monogamy refers to the frequency with which monogamy occurs.

This article deals with the incidence of monogamy in human beings. To learn about the incidence of monogamy in animals, which is generally lower than the incidence of monogamy in human beings, see the Wikipedia article on Animal Sexuality.

A large majority of human beings around the world enter socially monogamous relationships at some point in their lives. Most people who enter socially monogamous relationships remain sexually monogamous for the duration of the relationship. However, the amount of sexual monogamy varies across cultures, and women tend to be more sexually monogamous than men. Genetic monogamy also varies across cultures but is generally high overall.

Incidence of social monogamy

The United Nations World Fertility Report of 2003 reports that 89% percent of all women and men get married by age forty-nine.United Nations (2004). World Fertility Report: 2003. Retrieved April 26, 2006 from http://www.un.org/esa/population/publications/worldfertility/World_Fertility_Report.htm .] This is, of course, an average. The percent of women and men who marry by age forty-nine drops to nearly 50% in some nations and reaches 100% in other nations.United Nations (2000). World Marriage Patterns 2000. Retrieved April 26, 2006 from http://www.un.org/esa/population/publications/worldmarriage/worldmarriagepatterns2000.pdf .] On average, though, 89% of all people in the world marry by age forty-nine.

Not all marriages are socially monogamous. Anthropological studies have reported that 80-85% of societies allow polygamous marriage.Murdock, G.P. (1967). Ethnographic Atlas. Pittsburgh, PA: University of Pittsburgh Press.] White, D.R. & Veit, C. (1999). White-Veit EthnoAtlas. Retrieved April 28, 2006 from http://eclectic.ss.uci.edu/~drwhite/ethnoatlas/nindex.html.] Murdock, G. P. (1981). Atlas of World Cultures. Pittsburgh, PA: University of Pittsburgh Press.] Yet, most of the men in societies that allow polygamy do not obtain sufficient wealth or status to have multiple wives, so the majority of marriages in these societies involve one husband and one wife. Murdock has estimated that 80% of marriages in societies that allow polygamy involve only one husband and one wife.Murdock, G. P. (1981). Atlas of World Cultures. Pittsburgh, PA: University of Pittsburgh Press.] White has analyzed the distribution of husbands by number of wives in societies that allow polygamy (see Table 1 in White, 1988, pages 535-539).White, D.R. (1988). Rethinking polygyny: Co-wives, codes, and cultural systems. Current Anthropology, 29, 572.] His analysis also supports the claim that around 80% of marriages in these societies involve only one husband and one wife. In fact, so many marriages are socially monogamous that Murdock had years earlier stated:

"An impartial observer employing the criterion of numerical preponderance, consequently, would be compelled to characterize nearly every known human society as monogamous, despite the preference for and frequency of polygyny in the overwhelming majority.” (Murdock, 1949, pages 27-28) Murdock, G.P. (1949). Social Structure. New York: Free Press.]

Keep in mind the estimate of 80% socially monogamous marriages applies to societies where polygamous marriage is a legal or culturally accepted option. The percent of socially monogamous marriages is higher in societies where social monogamy is the only legal form of marriage. Social monogamy is the only legal form of marriage in several of the world’s most populous nations including China, members of the European Union, United States, Russia, and Japan. Based on population estimates from the CIA World Factbook 2006Central Intelligence Agency (2006). The World Factbook 2006. Retrieved April 30, 2006 from https://www.cia.gov/library/publications/the-world-factbook/index.html .] , a little over one-third of the world's population lives in these nations.

"Selected Populations from CIA World Factbook 2006"

Nation	Population
China	1,313,973,713
European Union members	456,953,258
United States	298,444,215
Russia	142,893,540
Japan	127,463,611
"Sum"	2,339,728,337
"World Total"	6,525,170,264
"Percent"	35.8%

Thus, a large majority of people enter socially monogamous relationships at some point in their lives. Almost 9 out of 10 people around the world marry by age 49. No fewer than 80% of these marriages are socially monogamous, and close to 100% of marriages are socially monogamous for one-third of the world's population.

Incidence of sexual monogamy

The incidence of sexual monogamy can be roughly estimated as the percentage of married people who do not engage in extramarital sex. Several studies have looked at the percentage of people who engage in extramarital sex. These studies have shown that extramarital sex varies across cultures and across genders.

The Standard Cross-Cultural Sample describes the amount of extramarital sex by men and women in over 50 pre-industrial cultures.Divale, W. (2000). Pre-Coded Variables for the Standard Cross-Cultural Sample, Volume I and II. Jamaica, NY: York College, CUNY. Distributed by World Cultures at http://worldcultures.org/SCCS1.pdf. See Variable 170 and Variable 171.] Murdock, G.P., & White, D.R. (1969). Standard cross-cultural sample. Ethnology, 8, 329-369.] The amount of extramarital sex by men is described as "universal" in 6 cultures, "moderate" in 29 cultures, "occasional" in 6 cultures, and "uncommon" in 10 cultures. The amount of extramarital sex by women is described as "universal" in 6 cultures, "moderate" in 23 cultures, "occasional" in 9 cultures, and "uncommon" in 15 cultures. These findings support the claim that the amount of extramarital sex differs across cultures and across genders.

Recent surveys conducted in non-Western nations have also found cultural and gender differences in extramarital sex. A study of sexual behavior in Thailand, Tanzania and Côte d'Ivoire suggests about 16-34% of men engage in extramarital sex while a much smaller (unreported) percentage of women engage in extramarital sex.O’Connor, M.L. (2001). Men who have many sexual partners before marriage are more likely to engage in extramarital intercourse. International Family Planning Perspectives, 27, 48-49.] Studies in Nigeria have found around 47-53% of men and to 18-36% of women engage in extramarital sex.Isiugo-Abanihe, U.C. (1994). Extramarital relations and perceptions of HIV/AIDS in Nigeria. Health Transition Review, 4, 111-125] Ladebo, O.J., & Tanimowo, A.G. (2002). Extension personnel's sexual behaviour and attitudes toward HIV/AIDS in South-Western Nigeria. African Journal of Reproductive Health, 6, 51-59.] A 1999 survey of married and cohabiting couples in Zimbabwe reports that 38% of men and 13% of women engaged in extra-couple sexual relationships within the last 12 months.National AIDS Council, Ministry of Health and Child Welfare, The MEASURE Project, Centers for Disease Control and Prevention (CDC/Zimbabwe). AIDS in Africa During the Nineties: Zimbabwe. A review and analysis of survey and research results. Carolina Population Center, University of North Carolina at Chapel Hill, 2002.]

Nowhere has extramarital sex been examined more frequently than in the United States. Many surveys asking about extramarital sex in the United States have relied on convenience samples. A convenience sample means surveys are given to whomever happens to be easily available (e.g., volunteer college students or volunteer magazine readers). Convenience samples do not accurately reflect the population of the United States as a whole, which can cause serious biases in survey results. It should not be surprising, therefore, that surveys of extramarital sex in the United States have produced widely differing results. A few studies relying on convenience samples have tried to compensate for biases by surveying large numbers of people. These studies report that about 12-26% of married women and 15-43% of married men engage in extramarital sex.Hunt, M. (1974). Sexual behavior in the 1970s. Chicago: Playboy Press. ] Blumstein, P., & Schwartz, P. (1983). American Couples: Money, Work, Sex. New York, NY: William Morrow and Company.] Janus, S.S. & Janus, C.L. (1993). The Janus Report on Sexual Behavior. New York, NY: John Wiley & Sons, Inc.] Although surveying large numbers of people helps to counteract the biases of convenience samples, the only way to get scientifically reliable estimates of extramarital sex is to use nationally representative samples. Three studies have used nationally representative samples. These studies have found that about 10-15% of women and 20-25% of men engage in extramarital sex.Clements, M. (1994, August 7). Sex in America today: A new national survey reveals how our attitudes are changing. Parade Magazine, 4-6.] Laumann, E. O., Gagnon, J. H., Michael, R. T, & Michaels, S. (1994). The social organization of sexuality: Sexual practices in the United States. Chicago: University of Chicago Press.] Macintyre, S. & Sooman, A. (1991). Non-paternity and prenatal genetic screening. Lancet, 338, 869-871.] Simmons, Firman, Rhodes, and Peters reviewed 11 published studies of extra-pair paternity from various locations in the United States, France, Switzerland, United Kingdom, Mexico, and the Yanomamo Indians in South America. Simmons, L.W., Firman, R.E.C., Rhodes, G., & Peters, M. (2004). Human sperm competition: testis size, sperm production and rates of extrapair copulations. Animal Behaviour, 68, 297-302.] The rates of exptrapair paternity ranged from 0.03% to 11.8% although most of the locations had low percentages of extrapair paternity. The median rate of extrapair paternity was 1.8%. A separate review of 17 studies by Bellis, Hughes, Hughes, and Ashton found slightly higher rates of extrapair paternity.Bellis, M.A., Hughes, K., Hughes, S., & Ashton, J.R. (2005). Measuring paternal discrepancy and its public health consequences. Journal of Epidemiology and Community Health, 59, 749-754] The rates varied from 0.8% to 30% in these studies, with a median rate of 3.7% extrapair paternity. A range of 1.8% to 3.7% extrapair paternity implies a range of 96% to 98% genetic monogamy. Although the incidence of genetic monogamy may vary from 70% to 99% in different cultures or social environments, a large percentage of couples remain genetically monogamous during their relationships. A review paper surveying 67 other studies of nonpaternity reporting rates of nonpaternity in different societies ranging from 0.4% to over 50% was recently published by Kermyt G. Anderson. [ [http://faculty-staff.ou.edu/A/Kermyt.G.Anderson-1/papers/worldwidepc.pdf "How Well Does Paternity Confidence Match Actual Paternity? Evidence from Worldwide Nonpaternity Rates, Kermyt G. Anderson, Current Anthropology 48(3): 511-518. 2006.] ]

Pedigree errors are a well-known source of error in medical studies. When attempts are made to try to study medical afflictions and their genetic components, it becomes very important to understand nonpaternity rates and pedigree errors. There are numerous software packages and procedures that exist for correcting research data for pedigree errors. [ [http://content.karger.com/ProdukteDB/produkte.asp?Doi=67666 "Enhanced Pedigree Error Detection", Lei Suna, Kenneth Wildera, Mary Sara McPeeka, Human Heredity 2002;54:99-110 (DOI: 10.1159/000067666)] ] [ [http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1377228 "PedCheck: a program for identification of genotype incompatibilities in linkage analysis", J R O'Connell and D E Weeks, Am J Hum Genet. 1998 July; 63(1): 259–266.] ] [ [http://www.citeulike.org/user/Ayest/article/939643 "Evaluating pedigree data. I. The estimation of pedigree error in the presence of marker mistyping," Lathrop GM, Hooper AB, Huntsman JW, Ward RH, Am J Hum Genet, Vol. 35, No. 2. (March 1983), pp. 241-262.] ]

ee also

* Monogamy
* Varieties of Monogamy
* Value of Monogamy
* Psychology of Monogamy
* Evolution of Monogamy
* Pair bonding
* Serial monogamy
* Open marriage
* Swinging
* Affair
* Forms of nonmonogamy
* Polyamory
* Polygamy
* Polyfidelity
* Group marriage
* Cohabitation
* Marriage
* Divorce
* Mating system
* Animal Sexuality
* Jealousy
* Cuckold

Bibliography

*

External links

* [http://www.childsupportanalysis.co.uk/analysis_and_opinion/choices_and_behaviours/misattributed_paternity.htm#philipp1973 UK website on childsupport and paternity with many links to studies of paternity, nonpaternity and pedigree error rates]
* [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=6585347&dopt=Abstract "Evaluating pedigree data. II. Identifying the cause of error in families with inconsistencies", Lathrop GM, Huntsman JW, Hooper AB, Ward RH, Hum Hered. 1983;33(6):377-89.]

References