Worldwide Census Data Reveal Prevalence of Educational Homogamy and Its Effect on Childlessness

Abstract

In a former study based on US census data, we found that educational homogamy is common and reduces the odds to remain childless. This study takes the next step and examines the prevalence of educational homogamy and its association with childlessness as well as the number of children on a worldwide basis. We analyzed census data from 41 different countries encompassing a total of 2,179,736 married women. In all investigated countries, the prevalence of educational homogamy is high. Furthermore, educational homogamy is not associated with a woman's average number of children, which generally increases with decreasing education. This is not the case as regards childlessness, however, which is usually reduced by a combination of moderate female hypergamy and homogamy. We conclude that educational homogamy is a universal phenomenon. We discuss that, together with its effects on childlessness, this may have consequences going beyond the individual to include the level of society and population genetics.

Marriage in the Melting Pot: An Evolutionary Approach to European Ancestry, Homogamy, and Fertility in the United States

“…Assortative mating and the prevalence of homogamy have often been documented, but a potential correlation between homogamy and reproduction has only been investigated for a few traits so far. Studies find that educational homogamy is particularly associated with a lower prevalence of childlessness ( Huber and Fieder, 2011 , 2016 ; Van Bavel, 2012 ), and religious homogamy is positively associated with both fertility and having at least one child ( Fieder and Huber, 2016 ). Moreover, religious homogamy may compensate for ethnic heterogamy in terms of reproduction and vice versa ( Huber and Fieder, 2018 ).…”

“…Based on previous studies, we assume that the share of individuals from a certain ancestry in a geographical region, education, and income influences the willingness to marry heterogamous ( Blau et al, 1982 ; Fieder et al, 2020 ) and if assortative mating is occurring by the chance or not. Furthermore, findings suggest ( Huber and Fieder, 2011 , 2016 , 2018 ; Fieder and Huber, 2016 ) that in homogamous relationships, the number of children is increasing and childlessness is decreasing, leading to fitness benefits. In detail we investigated (i) if a prevalence of ancestral homogamy exists; (ii) which factors influence the preference for an ancestral homogamous vs. heterogamous marriage; (iii) if ancestral homogamous vs. heterogamous marriages influence fertility (measured in the number of children and childlessness); and (iv) the inherited component of the tendency to marry homogamous or heterogamous.…”

Mutual compensation of the effects of religious and ethnic homogamy on reproduction

“…Homogamy, mating based on similarity, has been shown for various traits including age, education, as well as several physical and psychological characteristics (e.g., Huber & Fieder, ; Merikangas, ; Mascie‐Taylor, ; Penton‐Voak, Perrett, & Peirec, ; Qian, ; Speakman, Djafarian, Stewart, & Jackson, ; Susanne & Lepage, ). Two traits that may be particularly relevant with respect to homogamy are ethnicity and religion because homogamy along these traits increases the risk of social segregation—an effect that would be augmented in the case of a pro‐fertile effect of homogamy.…”