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Familial Resemblance in Religiousness in a Secular Society: A Twin Study

  • Dorte Hvidtjørn (a1), Inge Petersen (a1), Jacob Hjelmborg (a2), Axel Skytthe (a1), Kaare Christensen (a1) and Niels C. Hvidt (a3)...

It is well known that human behavior and individual psychological traits are moderately to substantially heritable. Over the past decade, an increasing number of studies have explored the genetic and environmental influence on religiousness. These studies originate predominantly from countries generally considered more religious than the very secular northern European countries. Comparisons of the results are complicated by diverse definitions of religiousness, but several studies indicate that the influence of the family environment is most predominant in early life, whereas genetic influences increase with age. We performed a population-based twin study of religiousness in a secular society using data from a Web-based survey sent to 6,707 Danish twins born 1970–1989, who were identified in the Danish Twin Registry. We applied Fishman's three conceptual dimensions of religiousness: cognition, practice, and importance. In all polygenic models and biometric analyses, we controlled for gender and age. The study sample comprised 2,237 same sex twins, a response rate of 45%. We found high correlations within both monozygotic and dizygotic twin pairs in most items of religiousness, indicating a large influence from shared environmental factors. Personal religiousness such as praying to God, believing in God, and finding strength and comfort in religion were more influenced by genetic factors than were social forms of religiousness such as church attendance. We found a small tendency for increasing genetic influence with increasing age for some religious items, but not for all.

Corresponding author
address for correspondence: Dorte Hvidtjørn, Epidemiology Unit, Institute of Public Health, University of Southern Denmark, J B Winsløvs Vej 9b, 5000 Odense, Denmark. E-mail:
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Allport, G. W., & Ross, J. M. (1967). Personal religious orientation and prejudice. Journal of Personality and Social Psychology, 5, 432443.
Ausker, N. (2008). Danske patienter intensiverer eksistentielle tanker og religiøst liv. Ugeskrift for Læger, 170, 21.
Bouchard, T. J. Jr., & McGue, M. (2003). Genetic and environmental influences on human psychological differences. Journal of Neurobiology, 54, 445.
Bouchard, T. J. Jr., McGue, M., Lykken, D., & Tellegen, A. (1999). Intrinsic and extrinsic religiousness: Genetic and environmental influences and personality correlates. Twin Research, 2, 8898.
Bradshaw, M., & Ellison, C. G. (2008). Do genetic factors influence religious life? Findings from a behavior genetic analysis of twin siblings. Journal for the Scientific Study of Religion, 47, 529544.
Christensen, K., Petersen, I., Skytthe, A., Herskind, A. M., McGue, M., & Bingley, P. (2006). Comparison of academic performance of twins and singletons in adolescence: Follow-up study. BMJ, 333, 10951097.
Christiansen, L., Frederiksen, H., Schousboe, K., Skytthe, A., von Wurmb-Schwark, N., Christensen, K., & Kyvik, K. (2003). Age and sex differences in the validity of questionnaire-based zygosity in twins. Twin Research, 6, 275278.
Finke, R. (1998). Religious choice and competition. American Journal of Sociology, 63, 761766.
Fishman, J. A. (1980). Social theory and ethnography: Language and ethnicity in Eastern Europe. In Sugar, P. F. (Ed.), Ethnic diversity and conflict in Eastern Europe (pp. 347371). Oxford: Clio Press.
Folkekirken (n.d.). Retrieved from
Francis, L. (1997). The psychology of gender differences in religion: A review of empirical research. Religion, 27, 8196.
Gallup, G. Jr., & Lindsay, D. M. (1999). Surveying the religious landscape. Trends in US beliefs. Harrisburg, PA: Morehouse Publishing.
Gundelach, P. (2006). EVS — European Values Study 1999/2000. Retrieved from
Gundelach, P., Iversen, H. R., & Warburg, M. (2008). I hjertet af Danmark — Institutioner og mentaliteter. Copenhagen: Hans Reitzels Forlag.
Haraldsson, E. (2006). Popular psychology, belief in life after death and reincarnation in the Nordic countries, Western and Eastern Europe. Nordic Psychology, 58, 171180.
Hill, P. C., & Pargament, K. I. (2003). Advances in the conceptualization and measurement of religion and spirituality: Implications for physical and mental health research. American Psychologist, 58, 6474.
Iversen, H. R. (Ed.) (2005). Gudstro i Danmark [Belief in God in Denmark]. Copenhagen: Anis.
Johnson, W., Krueger, R. F., Bouchard, T. J. Jr., & McGue, M. (2002). The personalities of twins: Just ordinary folks. Twin Research, 5, 125131.
Kendler, K. S., Gardner, C. O., & Prescott, C. A. (1997). Religion, psychopathology, and substance use and abuse: A multimeasure, genetic-epidemiologic study. American Journal of Psychiatry, 154, 322329.
Kendler, K. S., & Myers, J. (2009). A developmental twin study of church attendance and alcohol and nicotine consumption: A model for analyzing the changing impact of genes and environment. American Journal of Psychiatry, 166, 11501155.
Kirk, K. M., Eaves, L. J., & Martin, N. G. (1999a). Self-transcendence as a measure of spirituality in a sample of older Australian twins. Twin Research, 2, 8187.
Kirk, K. M., Maes, H. H., Neale, M. C., Heath, A. C., Martin, N. G., & Eaves, L. J. (1999b). Frequency of church attendance in Australia and the United States: Models of family resemblance. Twin Research, 2, 99107.
Kirkpatrick, A. (1997). A longitudinal study of changes in religious belief and behavior as a function of individual differences in adult attachment style. Journal for the Scientific Study of Religion, 36, 207217.
Koenig, L. (2011). The behavioral genetics of religiousness. Theology and Science, 9, 199212.
Koenig, L. B., McGue, M., Kreuger, R. F., & Bouchard, T. J. Jr. (2005). Genetic and environmental influences on religiousness: Findings for retrospective and current religiousness ratings. Journal of Personality, 73, 471488.
Koenig, L. B., McGue, M., & Lacono, W. G. (2008). Stability and change in religiousness during emerging adulthood. Developmental Psychology, 44, 532543.
la Cour, P. (2008). Existential and religious issues when admitted to hospital in a secular society: Patterns of change. Mental Health, Religion & Culture, 1, 114.
la Cour, P., & Hvidt, N. C. (2010). Research on meaning-making and health in secular society: Secular, spiritual and religious existential orientations. Social Science & Medicine, 71, 12921299.
Neale, M., Boker, S. M., Xie, G., & Maes, H. H. (2003). Mx: Statistical modeling (6th ed.). Richmond, VA: Department of Psychiatry, Medical College of Virginia.
Petersen, I., Martinussen, T., McGue, M., Bingley, P., & Christensen, K. (2011). Lower marriage and divorce rates among twins than among singletons in Danish birth cohorts 1940–1964. Twin Research and Human Genetics, 14, 150157.
Skytthe, A., Kyvik, K., Bathum, L., Holm, N., Vaupel, J. W., & Christensen, K. (2006). The Danish Twin Registry in the new millennium. Twin Research and Human Genetics, 9, 763771.
Skytthe, A., Kyvik, K. O., Holm, N. V., & Christensen, K. (2011). The Danish Twin Registry. Scandinavian Journal of Public Health, 39 (Suppl. 7), 7578.
Tomassini, C., Juel, K., Holm, N. V., Skytthe, A., & Christensen, K. (2003). Risk of suicide in twins: 51 year follow-up study. BMJ, 327, 373374.
Tsuang, M. T., Williams, W. M., Simpson, J. C., & Lions, M. J. (2002). Pilot study of spirituality and mental health in twins. American Journal of Psychiatry, 159, 486488.
Vance, T., Maes, H. H., & Kendler, K. S. (2010). Genetic and environmental influences on multiple dimensions of religiosity: A twin study. Journal of Mental and Nervous Disease, 198, 755761.
Warburg, M. (Ed.) (2007). Tørre tal om troen. Højbjerg, Denmark: Forlaget Univers.
Winter, T., Kaprio, J., Viken, R. J., Karvonen, S., & Rose, R. J. (1999). Individual differences in adolescent religiosity in Finland: Familial effects are modified by sex and region of residence. Twin Research, 2, 108114.
Wulff, D. H. (1997). Psychology of religion. Classic and contemporary (2nd ed.). New York: John Wiley & Son.
Zuckerman, P. (2008). Samfund Uden Gud. Højbjerg, Denmark: Forlaget Univers.
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Twin Research and Human Genetics
  • ISSN: 1832-4274
  • EISSN: 1839-2628
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