Genetic and Environmental Influences on Individual Differences in Attitudes Toward Homosexuality: An Australian Twin Study

Genetic Epidemiology Laboratory, Queensland Institute of Medical Research, 300 Herston Road, Brisbane 4029, QLD, Australia.
Behavior Genetics (Impact Factor: 3.21). 06/2008; 38(3):257-65. DOI: 10.1007/s10519-008-9200-9
Source: PubMed


Previous research has shown that many heterosexuals hold negative attitudes toward homosexuals and homosexuality (homophobia). Although a great deal of research has focused on the profile of homophobic individuals, this research provides little theoretical insight into the aetiology of homophobia. To examine genetic and environmental influences on variation in attitudes toward homophobia, we analysed data from 4,688 twins who completed a questionnaire concerning sexual behaviour and attitudes, including attitudes toward homosexuality. Results show that, in accordance with literature, males have significantly more negative attitudes toward homosexuality than females and non-heterosexuals are less homophobic than heterosexuals. In contrast with some earlier findings, age had no significant effect on the homophobia scores in this study. Genetic modelling showed that variation in homophobia scores could be explained by additive genetic (36%), shared environmental (18%) and unique environmental factors (46%). However, corrections based on previous findings show that the shared environmental estimate may be almost entirely accounted for as extra additive genetic variance arising from assortative mating for homophobic attitudes. The results suggest that variation in attitudes toward homosexuality is substantially inherited, and that social environmental influences are relatively minor.

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Available from: J. Michael Bailey, Oct 04, 2015
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    • "In fact, behavioral genetic studies on negative attitudes toward specific groups, such as homosexuals (Verweij et al. 2008) or hippies (Martin et al. 1986), have reported that more than one-third of the variance was attributable to genetic sources. Moreover, individual differences in attitudes toward white superiority, apartheid, and immigration as well as racial prejudice have been shown to be substantially genetically influenced (e.g., Hatemi et al. 2010; Loehlin 1993; Martin et al. 1986; Truett et al. 1992). "
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    ABSTRACT: This study quantified genetic and environmental roots of variance in prejudice and discriminatory intent toward foreign nationals and examined potential mediators of these genetic influences: right-wing authoritarianism (RWA), social dominance orientation (SDO), and narrow-sense xenophobia (NSX). In line with the Dual Process Motivational (DPM) model, we predicted that the two basic attitudinal and motivational orientations – RWA and SDO – would account for variance in out-group prejudice and discrimination. In line with other theories, we expected that NSX as an affective component would explain additional variance in out-group prejudice and discriminatory intent. Data from 1,397 individuals (incl. twins as well as their spouses) were analyzed. Univariate analyses of twins’ and spouses’ data yielded genetic (incl. contributions of assortative mating) and multiple environmental sources (i.e., social homogamy, spouse-specific, and individual-specific effects) of variance in negativity toward strangers. Multivariate analyses suggested an extension to the DPM model by including NSX in addition to RWA and SDO as predictor of prejudice and discrimination. RWA and NSX primarily mediated the genetic influences on the variance in prejudice and discriminatory intent toward foreign nationals. In sum, the findings provide the basis of a behavioral genetic framework integrating different scientific disciplines for the study of negativity toward out-groups.
    Behavior Genetics 03/2015; 45:181-199. DOI:10.1007/s10519-014-9700-8 · 3.21 Impact Factor
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    • "), and attitudes to homosexuality (Verweij et al., 2008) all contain heritable effects. For almost all of these observations, heritable effects accounted for between 25% and 50% of phenotypic variance, indicating that moderate-to-large genetic influences are common for social attitudes. "
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    Social Psychological and Personality Science 05/2014; 5(4):407-413. DOI:10.1177/1948550613504967 · 2.56 Impact Factor
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    • "An early finding from behavioral genetics research is now unsurprising: That enduring individual differences such as intelligence and personality are substantially (though not completely) heritable (Bouchard, 2004). From this base, researchers found that many presumably contextualized psychological variables are heritable to varying degrees , including outcomes both socially desirable [e.g., exercise participation (Bryan, Hutchison, Seals, & Allen, 2007), second language acquisition (Dale, Harlaar, Haworth, & Plomin, 2010), perceived social support (Bergeman, Neiderhiser, Pedersen, & Plomin, 2001), mental health (Keyes, Myers, & Kendler, 2010)] and undesirable [e.g., smoking (Boardman, Blalock, & Pampel, 2010), drug use (Haberstick et al., 2011), negative attitudes toward homosexuals (Verweij et al., 2008), psychiatric disorders (Khan, Jacobson, Gardner, Prescott, & Kendler, 2005)]. Indeed, genetic effects are so strong and pervasive that the proposition that all human characteristics are heritable has been labeled by Turkheimer (2000) as the First Law of Genetics. "
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    ABSTRACT: In this study we investigated the mediated influence of core self-evaluations (CSE) on employee health problems via job satisfaction and work stress, and the degree to which genetic factors explain these mediated relationships. Based on data obtained from a sample of 594 Swedish twins (114 monozygotic twin pairs and 183 dizygotic twin pairs), conventional path analysis results supported the mediated effects of CSE on employee health via job satisfaction and work stress, after controlling for conscientiousness and extraversion. Behavioral genetic analyses showed significant heritability of all four variables. Moreover, we found that the mediated relationships via job satisfaction and work stress are explained by genetic factors, such that the genetic source of job satisfaction and work stress mediates the genetic influence of CSE on health problems. These results highlight the role played by genetic factors in better understanding the relationships between CSE, work attitudes, and health outcomes.
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