The effect of school performance upon marriage and long-term reproductive success in 10,000 Swedish males and females born 1915–1929

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.

Less Is More? Repartnering and Completed Cohort Fertility in Finland

An extensive literature theorizes the role of repartnering for cohort fertility and whether union dissolution can be an engine for fertility. A large share of higher order unions are nonmarital cohabitations, but most previous studies on completed cohort fertility have analyzed only marital unions, and none have incorporated nonmarital cohabitations using population-level data. To analyze the relationship between the number of unions and cohort fertility for men and women, we use Poisson regression with Finnish register data to enumerate every birth, marriage, and cohabitation among the 1969-1972 birth cohorts at ages 18-46. We show that dissolutions of first cohabitations are the main pathway to repartnering and that most higher order unions are cohabitations. Nonmarital repartnering is a strong predictor of low fertility. In contrast, remarriage is positively associated with cohort fertility. Because the bulk of first-union dissolutions and higher order unions are nonmarital, repartnering is not an efficient engine for fertility at the aggregate level. Marriage and cohabitation are far from indistinguishable in a country often described as a second demographic transition forerunner.

Historical Context Changes Pathways of Parental Influence on Reproduction: An Empirical Test from 20th-Century Sweden

Several studies have found that parental absences in childhood are associated with individuals’ reproductive strategies later in life. However, these associations vary across populations and the reasons for this heterogeneity remain debated. In this paper, we examine the diversity of parental associations in three ways. First, we test whether different kinds of parental availability in childhood and adolescence are associated with women’s and men’s ages at first birth using the intergenerational and longitudinal Uppsala Birth Cohort Study (UBCoS) dataset from Sweden. This cultural context provides a strong test of the hypothesis that parents influence life history strategies given that robust social safety nets may buffer parental absences. Second, we examine whether investments in education help explain why early parental presence is associated with delayed ages at first birth in many post-industrial societies, given that parents often support educational achievement. Third, we compare parental associations with reproductive timing across two adjacent generations in Sweden. This historical contrast allows us to control for many sources of heterogeneity while examining whether changing educational access and norms across the 20th-century change the magnitude and pathways of parental influence. We find that parental absences tend to be associated with earlier first births, and more reliably so for women. Many of these associations are partially mediated by university attendance. However, we also find important differences across cohorts. For example, the associations with paternal death become similar for sons and daughters in the more recent cohort. One possible explanation for this finding is that fathers start influencing sons and daughters more similarly. Our results illustrate that historical changes within a population can quickly shift how family affects life history.

Sex Differences in the Association of Family and Personal Income and Wealth with Fertility in the United States

Evolutionary theory predicts that social status and fertility will be positively related. It also predicts that the relationship between status and fertility will differ for men and women. This is particularly likely in modern societies given evidence that females face greater trade-offs between status and resource acquisition and fertility than males. This paper tests these hypotheses using newly released data from the 2014 wave of the Survey of Income and Program Participation by the US Census, which has the first complete measures of fertility and number of childbearing partners for a large, representative, national probability sample of men and women and also contains comprehensive measures of economic status as measured by personal and family resources, including income from all sources and all assets. Multivariate analyses show that personal income is positively associated with total fertility and number of childbearing unions for men only. For men, personal net worth is positively associated with number of childbearing unions; it is also positively associated with fertility for married men with a spouse present. These findings support evolutionary predictions of a positive relationship between status, access to mates, and reproductive success for males. Whereas personal income and personal net worth are negatively associated with total fertility and number of childbearing unions for women, family income (net of personal income) is positively associated with total fertility for women. For married men living with a spouse, family income (net of personal income) is negatively associated with total fertility. These findings are consistent with evolutionary theory given the existence of greater trade-offs between production and reproduction for women in an advanced industrial society. For women and men, family net worth (net of personal net worth) is negatively associated with number of childbearing unions and fertility. Implications are discussed.

Effects of wife's and husband's income on wife's reproduction: an evolutionary perspective on human mating

From an evolutionary perspective, for women mate choice may be of crucial importance particularly concerning resources needed for rearing children. In modern societies, however, resources in terms of income are often provided by both women and men. Nonetheless, the effects of a wife's and husband's socioeconomic status on the wife's reproduction have not been investigated on a broader level. We therefore aim to investigate the effects of wife's and husband's income on wife's number of children and her probability of remaining childless using census data from nine countries mainly in the developing world for a total of 782,147 women aged 45-54 years who currently live with a husband and their spouses. Overall, both wife's and husband's income are significantly negatively associated with wife's number of children. Only in Israel do we find a positive association between husband's income and wife's offspring number. A wife's probability of remaining childless, however, increases with increasing own, but decreases with increasing husband's income. We conclude that in this sample of nearly all developing countries, effects of husband's socioeconomic status on wife's reproduction are acting through childlessness.

Biological, environmental and socioeconomic determinants of the human birth sex ratio in the Czech Republic

The Trivers-Willard Hypothesis (TWH) states that parents in good conditions bias the sex ratio towards sons and parents in poor conditions bias the sex ratio towards daughters. This study used data from a large nationwide population dataset (N=1,401,851) from the Czech Republic - a modern contemporary society. The study included air pollution and property prices in the TWH estimation, and had a more detailed focus on stillbirths than previous studies. Using official natality microdata from the Czech Statistical Office for years between 1992 and 2010 and data on levels of air pollution in the country over the same period, the study assessed whether the biological and socioeconomic status of mothers and environmental factors affected the sex of children. The results were largely insignificant and not robust across specifications. The presented epidemiological evidence suggests that stillbirths are randomly distributed in the Czech Republic and that the sex ratio is not affected by the socioeconomic status of mothers or by environmental characteristics.

Education, Other Socioeconomic Characteristics Across the Life Course, and Fertility Among Finnish Men

The level of education and other adult socioeconomic characteristics of men are known to associate with their fertility, but early-life socioeconomic characteristics may also be related. We studied how men’s adult and early-life socioeconomic characteristics are associated with their eventual fertility and whether the differences therein by educational level are explained or mediated by other socioeconomic characteristics. The data on men born in 1940–1950 (N = 37,082) were derived from the 1950 Finnish census, which is linked to later registers. Standard and sibling fixed-effects Poisson and logistic regression models were used. Education and other characteristics were positively associated with the number of children, largely stemming from a higher likelihood of a first birth among the more socioeconomically advantaged men. The educational gradient in the number of children was not explained by early socioeconomic or other characteristics shared by brothers, but occupational position and income in adulthood mediated approximately half of the association. Parity-specific differences existed: education and many other socioeconomic characteristics predicted the likelihood of a first birth more strongly than that of a second birth, and the mediating role of occupational position and income was also strongest for first births. Relatively small differences were found in the likelihood of a third birth. In men, education is positively associated with eventual fertility after controlling for early socioeconomic and other characteristics shared by brothers. Selective entry into fatherhood based on economic provider potential may contribute considerably to educational differentials in the number of children among men.

Genealogical Microdata and Their Significance for Social Science

Despite long-standing recognition of the importance of family background in shaping life outcomes, only recently have empirical studies in demography, stratification, and other areas begun to consider the influence of kin other than parents. These new studies reflect the increasing availability of genealogical microdata that provide information about ancestors and kin over three or more generations. These data sets, including family genealogies, linked vital registration records, population registers, longitudinal surveys, and other sources, are valuable resources for social research on family, population, and stratification in a multigenerational perspective. This article reviews relevant recent studies, introduces and presents examples of the most important sources of genealogical microdata, identifies key methodological issues in the construction and analysis of genealogical data, and suggests directions for future research.

Intelligence and Fitness: The Mediating Role of Educational Level

The evolutionary status of intelligence is not clear: It is positively related to various indicators of fitness but negatively to reproductive success as the most important fitness marker. In the present research, we explored the links between intelligence and three fitness indicators: number of children (short-term reproductive success), number of grandchildren (long-term reproductive success), and age at first birth. Participants were individuals in a postreproductive stage ( N = 191; mean age = 66.5 years). Intelligence had a positive correlation with short-term reproductive success and age at first birth but a negative correlation with long-term reproductive success. Participants' education turned out to be a significant mediator of the link between intelligence and criterion measures. The results showed that intelligence can elevate short-term reproductive success. Furthermore, individuals with higher intellectual abilities tended to delay reproduction, which negatively affected their long-term reproductive success. Education was revealed as a very important resource which affects the link between cognitive abilities and fitness, thus proving its evolutionary role in contemporary populations.

A Life-Course Study of Cognitive Reserve in Dementia--From Childhood to Old Age

OBJECTIVE

To test a life-course model of cognitive reserve in dementia and examine if school grades around age 10 years, formal educational attainment, and lifetime occupational complexity affect the risk of dementia in old age.

METHODS

7,574 men and women from the Uppsala Birth Cohort Multigenerational Study were followed for 21 years. Information on school performance, formal education, and occupational attainment was collected prospectively from elementary school archives and population censuses. Dementia diagnosis was extracted from the two Swedish registers. Discrete-time Cox proportional hazard models were estimated.

RESULTS

Dementia was diagnosed in 950 individuals (12.5%). Dementia risk was lower among individuals with higher childhood school grades (hazard ratio [HR]: 0.79; 95% confidence interval [CI]: 0.68 to 0.93) and was lower among individuals in data-complex occupations (HR: 0.77; 95% CI: 0.64 to 0.92). Professional/university education predicted lower risk of dementia in minimally adjusted models (HR: 0.74; 95% CI: 0.60 to 0.91), although the effect faded with adjustment for occupational complexity. Lowest risk was found in the group with both higher childhood school performance and high occupational complexity with data (HR: 0.61; 95% CI: 0.50 to 0.75). Importantly, high occupational complexity could not compensate for the effect of low childhood grades. In contrast, dementia risk was reduced in those with higher school grades, irrespective of occupational complexity.

CONCLUSION

Higher childhood school performance is protective of dementia risk, particularly when preserved through complex work environments in adulthood, although it will remain protective even in the absence of later-life educational or occupational stimulation.

Ancestry Matters: Patrilineage Growth and Extinction

Patrilineality, the organization of kinship, inheritance, and other key social processes based on patrilineal male descent, has been a salient feature of social organization in China and many other societies for centuries. Because continuity or growth of the patrilineage was the central focus of reproductive strategies in such societies, we introduce the number of patrilineal male descendants generations later as a stratification outcome. By reconstructing and analyzing 20,000 patrilineages in two prospective, multi-generational population databases from 18th and 19th century China, we show that patrilineages founded by high status males had higher growth rates for the next 150 years. The elevated growth rate of these patrilineages was due more to their having a lower probability of extinction at each point in time than to surviving patrilineal male descendants having larger numbers of sons on average. As a result, patrilineal male descendants of high status males account for a disproportionately large share of the male population in later generations. In China and elsewhere, patrilineal kin network characteristics influence individuals' life chances; thus effects of a male founder's characteristics on patrilineage size many generations later represent an indirect channel of status transmission that has not been considered previously.

En bloc kidney transplant from young pediatric donors: a scope to increase the donor pool

We report 2 cases of en bloc kidney transplants from young pediatric donors with successful outcomes. We underscore the underuse of this significant donor source, and discuss the factors that may be related to the reasons for reluctance in accepting these kidneys for transplant.