This article relies largely or entirely on a single source. (October 2011)
Endogamy is common in many cultures and ethnic groups. Several ethnic religious groups are traditionally more endogamous, although sometimes with the added dimension of requiring marital religious conversion. This permits an exogamous marriage, as the convert, by accepting the partner's religion, becomes accepted within the endogamous rules. Certain groups, such as Orthodox Jews adhering to endogamy in Judaism, have practised endogamy as an inherent part of their religious beliefs and traditions.
Endogamy can serve as a form of self-segregation; a community can use it to resist integrating and completely merging with surrounding populations. Minorities can use it to stay ethnically homogeneous over a long time as distinct communities within societies with other practices and beliefs.
The isolationist practices of endogamy may lead to a group's extinction, as genetic diseases may develop that can affect a larger percentage of the population. However, this disease effect would tend to be small unless there is a high degree of close inbreeding, or if the endogamous population becomes very small in size.
The Urapmin—a small tribe in Papua New Guinea—practice strict endogamy. The Urapmin also have a system of kinship classes known as tanum miit. Since the classes are inherited cognatically, most Urapmin belong to all of the major classes, creating great fluidity and doing little to differentiate individuals.
The small community on the South Atlantic island of Tristan da Cunha are, because of their geographical isolation, an almost endogamic society. There are instances of health problems attributed to endogamy on the island, including glaucoma and asthma as research by the University of Toronto has demonstrated.
Other examples of ethnic and religious groups that practice endogamy include:
- Anti-miscegenation laws
- Arranged marriage
- Assortative mating
- Ethnic nationalism
- Ethnic nepotism
- Ethnoreligious group
- Interfaith marriage
- Robbins, Joel (2004). Becoming Sinners: Christianity and Moral Torment in a Papua New Guinea Society. University of California Press. pp. 191–192. ISBN 0-520-23800-1.
- "Worldwide search for asthma clue". BBC News. 9 December 2008. Retrieved 15 March 2012.