title: Familial resemblance in religiousness in a secular society: a twin study.
abstract: 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.
authors: Institute of Public Health, University of Southern Denmark, Odense, Denmark. dhvidtjoern@health.sdu.dk
authors: Dorte
authors: D
authors: Hvidtjørn
authors: Inge
authors: I
authors: Petersen
authors: Jacob
authors: J
authors: Hjelmborg
authors: Axel
authors: A
authors: Skytthe
authors: Kaare
authors: K
authors: Christensen
authors: Niels C
authors: NC
authors: Hvidt
mesh_terms: D000328:Adult; D015331:Cohort Studies; D003469:Culture; D005260:Female; D006801:Humans; D040582:Inheritance Patterns; D008297:Male; D008960:Models, Psychological; D010551:Personality / Q000235:genetics; D012042:Registries; D012067:Religion; D035621:Secularism; D014429:Twins, Dizygotic / Q000235:genetics* / Q000523:psychology; D014430:Twins, Monozygotic / Q000235:genetics* / Q000523:psychology; D055815:Young Adult