Do income and marriage mediate the relationship between cognitive ability and fertility? Data from Swedish taxation and conscriptions registers for men born 1951–1967

Increasing pressure on US men for income in order to find a spouse

In contemporary societies, social status - especially income - is one of the most important determinants of ever marrying among men. Using U.S. census data, we estimated the importance of income for ever marrying among men and women, analyzing birth cohorts from 1890 to 1973. We examined individuals between the ages of 45 and 55, a total of 3.5 million men and 3.6 million women. We find that for men, the importance of income in predicting ever being married increased steadily over time. Income predicted only 2.5% of the variance in ever marrying for those born in 1890-1910, but about 20% for the 1973 cohort. For women, the opposite is true: the higher a woman's income among those born between 1890 and 1910, the lower her odds of ever being married, explaining 6% of the variance, whereas today a woman's income no longer plays a role in ever being married. Thus, our results provide evidence that income may represent a very recent selection pressure on men in the US, a pressure that has become increasingly stronger over time in the 20th and early 21st centuries.

The prospective power of personality for childbearing: a longitudinal study based on data from Germany

The link between personality and fertility is relatively underexplored. Moreover, there are only a few studies focusing on the prospective association between personality and childbearing. However, none of these studies considered the Five-Factor Model (FFM), which is the most widely accepted measurement of personality. The present study fills this gap by examining the prospective association between the FFM and the hazard ratio of the first and the second childbirth in Germany. Analyses are based on recent data (2005–2017) from the Socio-economic Panel Study. Cox proportional hazard models are applied. Findings demonstrate that personality traits are associated with fertility. Extraversion is positively linked with the first childbirth, but is negatively associated with the second childbirth. These findings are mainly driven by males. Agreeableness is positively linked with the first childbirth across the total sample. Again, this correlation is mainly based on the findings for men, among whom a positive association between agreeableness and the second childbirth is also found. Among women, personality does not seem to be linked with the first childbirth. However, the risk of having a second child is found to be negatively associated with conscientiousness. My study adds to the current understanding of the personality–fertility association by exploring the impact of personality trait scores from the FFM on subsequent fertility behavior. However, further research is needed on the association between personality and childbearing; on the mechanisms through which personality affects fertility; and on how these links differ across cultures, among higher parities, and for births after re-partnering.

Is paternal height related to fertility outcomes? Evidence from the Netherlands during the secular growth trend

Over the past two centuries, the Dutch experienced a tremendous secular trend in height, and ultimately became the tallest nation in the world. Improving environmental conditions likely played the largest role in explaining these developments. But it is not yet precisely clear what factor set the Dutch head and shoulders above other nations, who were also experiencing improving environmental conditions. Could fertility also have played a role? To understand this, we would first need to know whether height and fertility were related during the secular growth trend. In this study, we investigated whether this was the case. A sample of Dutch men, birth years 1850-1900 (n = 3396), was examined. We tested the extents to which height was associated with having a certain number of children, and with having a certain number of children survive infancy. Multinomial logistic regressions were used. In terms of findings, height's relationship to fertility outcomes was curvilinear: being shorter-than-average (0.75-0.5 standard deviations below the mean height) was associated with a higher probability of being married and having five to seven children, while being moderately tall (0.5 standard deviations above the mean height) was associated with the lowest probability of being unmarried. There was no relationship between paternal height and children surviving infancy in the sample overall, but taller height was associated with a decreased risk of being in a high-mortality family among men born between 1880 and 1900. If paternal fertility played a role in the secular growth trend, we would expect to see very tall men have the most children, and clearly have the most children surviving infancy. Given this study's findings, it is unlikely that this was the case.

Fading family lines- women and men without children, grandchildren and great-grandchildren in 19th, 20th and 21st Century Northern Sweden

We studied to what extent family lines die out over the course of 122 years based on Swedish population-level data. Our data included demographic and socioeconomic information for four generations in the Skellefteå region of northern Sweden from 1885 to 2007. The first generation in our sample consisted of men and women born between 1885 and 1899 (N = 5850), and we observed their children, grandchildren, and great-grandchildren. We found that 48% of the first generation did not have any living descendants (great-grandchildren) by 2007. The risk of a family line dying out within the four-generational framework was highest among those who had relatively low fertility in the first generation. Mortality during reproductive years was also a leading reason why individuals in the first generation ended up with a greater risk of not leaving descendants. We identified socioeconomic differences: both the highest-status and the lowest-status occupational groups saw an increased risk of not leaving any descendants. Almost all lineages that made it to the third generation also made it to the fourth generation.

Social status predicts different mating and reproductive success for men and women in China: evidence from the 2010–2017 CGSS data

Abstract

Evolutionary psychological theories posit that higher social status is conducive to men’s reproductive success. Extant research from historical records, small scale societies, as well as industrialized societies, support this hypothesis. However, the relationship between status difference between spouses and reproductive success has been investigated less. Moreover, even fewer studies have directly compared the effect of status and status difference between spouses on reproductive success in men and women. Using data from the Chinese General Social Survey (CGSS) conducted between 2010 and 2017 (N = 55,875; 28,931 women) and operationalizing social status as standardized income and educational level (compared with same-sex peers), we examined how social status and relative status between spouses impact men’s and women’s mating and reproductive success. We found that (1) men with higher social status were more likely to have long-term mating (being in a marriage and/or not going through marriage disruption) and reproductive success, mainly through having a lower risk of childlessness; (2) women with higher social status were less likely to have mating and reproductive success; and (3) relative status between spouses had an impact on the couple’s reproductive success so that couples, where the husband had higher status compared to the wife, had higher reproductive success. Thus, social status positively impacted men’s reproductive success, but relative status between spouses also affected mating and impacted childbearing decisions.

Significance statement

In terms of standardized educational level and income among peers, social status positively predicts men’s mating and reproductive success in contemporary China. However, while a higher social status increases the probability of having at least one child, it does not predict a greater number of children for men. A status difference between spouses, on the other hand, consistently predicts having children. Thus, the higher the husband’s status relative to his wife, the greater the likelihood of having the first, second, and third children. The current results suggest that when examining the effect of status on mating and reproduction, social status and status within a family should be considered. We also stress the importance of exploring the potential proximate mechanisms by which a status difference influences childbearing decisions.

Husband's income, wife's income, and number of biological children in the U.S

Previous studies have found that the positive relationship between personal income and fertility for men in the United States is primarily due to childlessness among low-income men. Yet because of the opposite effects of income on fertility for men and women, it is important to examine the effects of income net of spouse's income. An analysis of income from all sources and biological fertility data for husbands and wives from the Survey of Income and Program Participation (2014) shows that for men their own income is positively associated with the number of their biological children, while their spouse's income is negatively associated with total children ever fathered. The reverse is true for women. These results are not because of childlessness among low-income men and high-income women, but also hold true among all those with children. For men and women aged 45-65, who likely have completed fertility, these results hold regardless of whether or not education is controlled. These findings suggest that if status is measured as personal income for men and husband's income for women, the positive relationship between status and fertility persists in a postdemographic transition society.

Parental status in later life and parents' risk of cognitive impairment

Parental status can influence parents’ well-being in significant ways, but little research has examined its impact on older adults’ cognitive health in the U.S. Using data from the National Health and Aging Trends Study (NHATS) 2011–2019, this study examines whether parental status is related to the risk of cognitive impairment among older adults in the U.S. We found that the presence of adult children (i.e., having at least one living adult child) was associated with a lower risk of cognitive impairment for older parents. Moreover, compared to childless older adults, older parents who had three and more children, who had adult daughter(s), and who had biological/adopted adult children displayed a significantly lower risk of cognitive impairment. This study highlights the importance of adult children as resources of support and caring that may benefit older parents’ cognitive health. The findings can help to identify the most vulnerable subpopulations among aging adults so that medical workers and policy makers can design effective strategies to protect cognitive function for those “at risk” older adults.

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Parental status is an important factor related to older adults’ cognitive health.

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Presence of adult children was associated with a lower risk of cognitive impairment than being childlessness.

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Having 3+ children, adult daughter(s), or biological children was associated with lower risk of cognitive impairment.