Fertility Outcomes, Heritability and Genomic Associations of In-Group Preference and In-Group Marriage

Using data from the Midlife Development in the USA (MIDUS) sample (3070 men and 3182 women) and the Wisconsin Longitudinal Study (WLS; 2240 men and 2346 women), we aimed to investigate whether religious, ethnic and racial in-group preferences as well as religious homogamy are associated with reproductive outcome in terms of number of children. Using data from the MIDUS twin sample, we further estimated the inherited genetic component of in-group attitudes. Additionally, we analyzed the association of ∼50 polygenic scores (PGSs) recently published for the WLS study and in-group attitudes as an indicator of potential pleiotropic effects. We found in both samples that, with one exception, religious though not other in-group attitudes are associated with a higher reproductive outcome. Also, religious homogamy is associated with higher average number of children. The inherited component of all in-group attitudes ranges from ∼21% to 45% (MIDUS twin sample). PGSs associated with religious behavior are significantly positively associated with religious in-group attitudes as well as family attitudes. Further associations are found with PGS on life satisfaction (work) and, negatively, with PGS for any sort of addiction (smoking, alcohol and cannabis use), indicating pleiotropy. We conclude that the positive association between religious in-group attitudes as well as religious homogamy and reproductive outcome may indicate selective forces on religious in-group behavior. As all investigated in-group attitudes, however, have a substantial inherited component, we further speculate that potential previous reproductive benefits of racial and ethnic in-group preferences, if they ever existed, might have been substituted by religious in-group preferences.

Religious Homogamy Affects the Connections of Personality and Marriage Qualities to Unforgiving Motives: Implications for Couple Therapy

In Ghana, collectivism holds people together in marital relationships, even if partners are religiously different. Married partners still hurt, betray, or offend each other and might develop avoidance or vengeful (i.e., unforgiving) motives. We investigated whether religious homogamy moderated connections of personality and marriage variables to unforgiving motives. Heterosexual married couples (N = 176 heterosexual married couples; N = 352 individuals; mean marriage duration 10.89 years) participated. Most identified as Christian (83.5% males; 82.3% females) or Muslim (11.9% males; 14.3% females). Couple religious homogamy was related directly to lower unforgiving motives. Religious homogamy did not moderate the connection between some personality variables (i.e., agreeableness and trait forgivingness) and unforgiving motives. Religiously unmatched couples tended to have greater unforgiveness at higher levels of neuroticism and lower forbearing, marital satisfaction, and marital commitment relative to religiously matched couples. One implication is that couple therapists need to assess partner neuroticism, marriage climate (i.e., satisfaction and commitment), and the general tendency to forbear when offended. Those can combine to produce unforgiving relationships, which might make progress in couple therapy improbable.

Marital Religious Homogamy and Dimensions of Well-Being in Later Life: Evidence From the United States

Past research points to the importance of couple-level religious similarity for multiple dimensions of older adults’ partnership quality and stability, but we have a limited understanding of whether religious homogamy matters for the well-being of seniors. This study uses dyadic data from the National Social Life, Health, and Aging Project (NSHAP), a representative sample of 953 individuals ages 62–91 plus their marital or cohabiting partners. Using actor-partner interdependence models in the general structural equation model framework (GSEM), we find that religious attendance homogamy is beneficial for the physical health of men and the mental health and self-reported happiness of women. There were no associations between religious homogamy for religious importance detected. Taken together, our results attest to the ongoing importance of religious similarity—service attendance, in particular—for mental and physical well-being in later life. Future research is needed to more fully examine which mechanisms account for these patterns.

Social Reproduction of Religiosity in the Immigrant Context: The Role of Family Transmission and Family Formation — Evidence from France

This paper compares two aspects of the social reproduction of religion: parent-to-child transmission, and religious homogamy. Analysis of a survey of immigrants in France shows that for parent-to-child transmission, immigrant status/generation is not the central variable — rather, variation is across religions with Muslim families showing high continuity. Immigrant status/generation does directly matter for partner choice. In Christian and Muslim families alike, religious in-partnering significantly declines in the second generation. In turn, the offspring of religiously non-homogamous families is less religious. For Muslim immigrants this points to the possibility of a non-trivial decline in religiosity in the third generation.

The association between religious homogamy and reproduction

Individuals more strongly affiliated to religion have on average more children than less religious ones. Here, based on census data of 3 658 650 women aged 46–60 years from 32 countries provided by IPUMS International and data from the Wisconsin Longitudinal Study ( n = 2400 women, aged 53–57 years), we show that religious homogamy is also associated with higher reproduction in terms of a higher number of children and a lower chance of remaining childless. We argue that, together with the relationship between general religious intensity and number of children, religious homogamy has reproductive consequences. These may impact future demographic developments and could have also played a role in the biological evolution of humans.