Intergenerational transmission of reproductive behavior during the demographic transition

What is driving the global decline of human fertility? Need for a multidisciplinary approach to the underlying mechanisms

An intense period of human population expansion over the past 250 years is about to cease. Total fertility rates are falling dramatically all over the world such that highly industrialized nations, including China and the tiger economies of SE Asia, will see their populations decline significantly in the coming decades. The socioeconomic, geopolitical and environmental ramifications of this change are considerable and invite a multidisciplinary consideration of the underlying mechanisms. In the short-term, socioeconomic factors, particularly urbanization and delayed childbearing are powerful drivers of reduced fertility. In parallel, lifestyle factors such as obesity and the presence of numerous reproductive toxicants in the environment, including air-borne pollutants, nanoplastics and electromagnetic radiation, are seriously compromising reproductive health. In the longer term, it is hypothesized that the reduction in family size that accompanies the demographic transition will decrease selection pressure on high fertility genes leading to a progressive loss of human fecundity. Paradoxically, the uptake of assisted reproductive technologies at scale, may also contribute to such fecundity loss by encouraging the retention of poor fertility genotypes within the population. Since the decline in fertility rate that accompanies the demographic transition appears to be ubiquitous, the public health implications for our species are potentially devastating.

Intergenerational transmission of fertility in Spain among cohorts born during the first half of twentieth century

It is known that historically fertility is correlated between generations of the same family. These links tend to be explained either in terms of the biogenetic determinants of reproduction or by the transmission of intra-familial values associated with reproduction and family life. Less is known about the micro-determinants of these links or about the extent to which the progressive modernization of reproductive outcomes over the past century has affected behavior. In this paper, we will address these issues for Spain with data from the Socio-Demographic Survey (SDS) carried out in 1991 and including data on cohorts born between 1900 and 1946. These data enable us to explore the micro determinants of fertility at different points of time during this period. Our results point to the existence of a significant correlation between intergenerational reproductive outcomes that persists and strengthens throughout this period of demographic change. Results confirm the importance of birth order in large family groups where firstborn offspring are more likely to have larger families than subsequent siblings. There is also evidence that the strength of these intergenerational ties increases with the onset of more modern demographic behavior characterized by sharply declining fertility. The results presented here promise to condition future debates on the subject.

The Influence of Kin Proximity on the Reproductive Success of American Couples, 1900-1910

Children require a large amount of time, effort, and resources to raise. Physical help, financial contributions, medical care, and other types of assistance from kin and social network members allow couples to space births closer together while maintaining or increasing child survival. We examine the impact of kin availability on couples' reproductive success in the early twentieth-century United States with a panel data set of over 3.1 million couples linked between the 1900 and 1910 U.S. censuses. Our results indicate that kin proximity outside the household was positively associated with fertility, child survival, and net reproduction, and suggest that declining kin availability was an important contributing factor to the fertility transition in the United States. We also find important differences between maternal and paternal kin inside the household-including higher fertility among women residing with their mother-in-law than among those residing with their mother-that support hypotheses related to the contrasting motivations and concerns of parents and parents-in-law.

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.

Is the Family Size of Parents and Children Still Related? Revisiting the Cross-Generational Relationship Over the Last Century

In most developed countries, the fertility levels of parents and children are positively correlated. This article analyzes the strength of the intergenerational transmission of family size over the last century, including a focus on this reproduction in large and small families. Using the large-scale French Family Survey (2011), we show a weak but significant correlation of approximately 0.12–0.15, which is comparable with levels in other Western countries. It is stronger for women than men, with a gender convergence across cohorts. A decrease in intergenerational transmission is observed across birth cohorts regardless of whether socioeconomic factors are controlled, supporting the idea that the family of origin has lost implicit and explicit influence on fertility choices. As parents were adopting the two-child family norm, the number of siblings lost its importance for having two children, but it continues to explain lower parity and, above all, three-child families. This suggests that the third child has increasingly become an “extra child” (beyond the norm) favored by people from large families.

Quantifying Interdisciplinary History - The Record of (nearly) fifty years

From its very beginnings, the JIH published articles that embraced quantitative methods, but in its effort to engage as many disciplines as possible, it did much more. Over the nearly fifty years of its publishing history, it has continued to publish variegated interdisciplinary material and, in the process, to present leading-edge research. Within the last ten years, however, the journal has acquired a new role in a much more international context. The emergence of new quantitative methods has permitted the JIH to redefine interdisciplinarity. Immense data sets, with modes of interpretation drawn from the social sciences as well as from the humanities, natural sciences, and medicine, will certainly continue to revolutionize future research in history and cognate disciplines.

Fertility decline in the United States, 1850-1930: New Evidence from Complete-Count Datasets

Between 1835 and 1935, total fertility in the United States fell from 7.0 to 2.1. New IPUMS complete-count microdata databases of the 1850, 1880, 1910, and 1930 U. S. censuses allow us to study the fertility decline in more detail than previously possible. We construct comprehensive models of couples' fertility incorporating a wide variety of economic, social, cultural and familial factors, including measures of parental religiosity and kin availability outside of the household. The results indicate that while shifts in the occupational structure and increasing urbanization of the population provide the most consistent and substantive contribution to fertility decline over the period, cultural and religious attitudes - as proxied by parents' nativities and child naming practices - played a major role in couples' childbearing decisions.

Intergenerational abortion tendency between mothers and teenage daughters: a population-based cohort study

BACKGROUND

A teenage woman's sexual health practices may be influenced by her mother's experience. We evaluated whether there is an intergenerational tendency for induced abortion between mothers and their teenage daughters.

METHODS

We conducted a retrospective population-based cohort study involving daughters born in Ontario between 1992 and 1999. We evaluated the daughters' data for induced abortions between age 12 years and their 20th birthday. We assessed each mother's history of induced abortion for the period from 4 years before her daughter's birth to 12 years after (i.e., when her daughter turned 12 years of age). We used Cox proportional hazard models to estimate a daughter's risk of having an induced abortion in relation to the mother's history of the same procedure. We adjusted hazard ratios (HRs) for maternal age and world region of origin, mental or physical health problems in the daughter, mother- daughter cohabitation, neighbourhood-level rate of teen induced abortion, rural or urban residence, and income quintile.

RESULTS

A total of 431 623 daughters were included in the analysis. The cumulative probability of teen induced abortion was 10.1% (95% confidence interval [CI] 9.8%-10.4%) among daughters whose mother had an induced abortion, and 4.2% (95% CI 4.1%-4.3%) among daughters whose mother had no induced abortion, for an adjusted HR of 1.94 (95% CI 1.86-2.01). The adjusted HR of a teenaged daughter having an induced abortion in relation to number of maternal induced abortions was 1.77 (95% CI 1.69-1.85) with 1 maternal abortion, 2.04 (95% CI 1.91-2.18) with 2 maternal abortions, 2.39 (95% CI 2.19-2.62) with 3 maternal abortions and 2.54 (95% CI 2.33-2.77) with 4 or more maternal abortions, relative to none.

INTERPRETATION

We found that the risk of teen induced abortion was higher among daughters whose mother had had an induced abortion. Future research should explore the mechanisms for intergenerational induced abortion.

Historical Census Record Linkage

For the past 80 years, social scientists have been linking historical censuses across time to study economic and geographic mobility. In recent decades, the quantity of historical census record linkage has exploded, owing largely to the advent of new machine-readable data created by genealogical organizations. Investigators are examining economic and geographic mobility across multiple generations, but also engaging many new topics. Several analysts are exploring the effects of early-life socioeconomic conditions, environmental exposures, or natural disasters on family, health and economic outcomes in later life. Other studies exploit natural experiments to gauge the impact of policy interventions such as social welfare programs and educational reforms. The new data sources have led to a proliferation of record linkage methodology, and some widespread approaches inadvertently introduce errors that can lead to false inferences. A new generation of large-scale shared data infrastructure now in preparation will ameliorate weaknesses of current linkage methods.

"Big data" in economic history

Big data is an exciting prospect for the field of economic history, which has long depended on the acquisition, keying, and cleaning of scarce numerical information about the past. This article examines two areas in which economic historians are already using big data - population and environment - discussing ways in which increased frequency of observation, denser samples, and smaller geographic units allow us to analyze the past with greater precision and often to track individuals, places, and phenomena across time. We also explore promising new sources of big data: organically created economic data, high resolution images, and textual corpora.

The impact of kin availability, parental religiosity, and nativity on fertility differentials in the late 19th-century United States

METHODS

Most quantitative research on fertility decline in the United States ignores the potential impact of cultural and familial factors. We rely on new complete-count data from the 1880 U.S. census to construct couple-level measures of nativity/ethnicity, religiosity, and kin availability. We include these measures with a comprehensive set of demographic, economic, and contextual variables in Poisson regression models of net marital fertility to assess their relative importance. We construct models with and without area fixed effects to control for unobserved heterogeneity.

CONTRIBUTION

All else being equal, we find a strong impact of nativity on recent net marital fertility. Fertility differentials among second generation couples relative to the native-born white population of native parentage were in most cases less than half of the differential observed among first generation immigrants, suggesting greater assimilation to native-born American childbearing norms. Our measures of parental religiosity and familial propinquity indicated a more modest impact on marital fertility. Couples who chose biblical names for their children had approximately 3% more children than couples relying on secular names while the presence of a potential mother-in-law in a nearby households was associated with 2% more children. Overall, our results demonstrate the need for more inclusive models of fertility behavior that include cultural and familial covariates.

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.

Like Mother(-in-Law) Like Daughter? Influence of the Older Generation's Fertility Behaviours on Women's Desired Family Size in Bihar, India

This paper investigates the associations between preferred family size of women in rural Bihar, India and the fertility behaviours of their mother and mother-in-law. Scheduled interviews of 440 pairs of married women aged 16–34 years and their mothers-in-law were conducted in 2011. Preferred family size is first measured by Coombs scale, allowing us to capture latent desired number of children and then categorized into three categories (low, medium and high). Women’s preferred family size is estimated using ordered logistic regression. We find that the family size preferences are not associated with mother’s fertility but with mother’s education. Mother-in-law’s desired number of grandchildren is positively associated with women’s preferred family size. However, when the woman has higher education than her mother-in-law, her preferred family size gets smaller, suggesting that education provides women with greater autonomy in their decision-making on childbearing.

Social network- and community-level influences on contraceptive use: evidence from rural Poland

The diffusion of 'modern' contraceptives-as a proxy for the spread of low-fertility norms-has long interested researchers wishing to understand global fertility decline. A fundamental question is how local cultural norms and other people's behaviour influence the probability of contraceptive use, independent of women's socioeconomic and life-history characteristics. However, few studies have combined data at individual, social network and community levels to simultaneously capture multiple levels of influence. Fewer still have tested if the same predictors matter for different contraceptive types. Here, we use new data from 22 high-fertility communities in Poland to compare predictors of the use of (i) any contraceptives-a proxy for the decision to control fertility-with those of (ii) 'artificial' contraceptives-a subset of more culturally taboo methods. We find that the contraceptive behaviour of friends and family is more influential than are women's own characteristics and that community level characteristics additionally influence contraceptive use. Highly educated neighbours accelerate women's contraceptive use overall, but not their artificial method use. Highly religious neighbours slow women's artificial method use, but not their contraceptive use overall. Our results highlight different dimensions of sociocultural influence on contraceptive diffusion and suggest that these may be more influential than are individual characteristics. A comparative multilevel framework is needed to understand these dynamics.

Occupation and fertility on the frontier: Evidence from the state of Utah

BACKGROUND

Most of what we know about fertility decline in the United States comes from aggregate (often state or county level) data sources. It is difficult to identify variation in fertility change across socio-economic classes in such data, although understanding such variation would provide deeper insight into the history of the fertility transition.

OBJECTIVE

We use rich micro-level data to examine differences across occupational classes in fertility levels and in the timing and pace of change in fertility in the US state of Utah in the late 19^th and early 20^th centuries.

METHODS

Our evidence comes from the Utah Population Database, which contains several generations of linked family histories, including information on residents of Utah from the mid-1800s to the present. We use standard linear regression models to identify variation in fertility across birth cohorts and occupational classes as well as cohort-occupation interaction effects (to identify differences across classes in the pace of change over time)

RESULTS

Families of white collar workers led changes in many fertility-related behaviors, particularly those tied to the start of family life (marriage age and first birth interval). Farm families had high fertility levels and added children into late ages, although they also experienced declining fertility.

CONCLUSIONS

Examination of detailed micro-level data on fertility change identifies important differences in the patterns of change which may be tied to variation in relevant economic circumstances – for instance, the length of education and training required for particular occupations, or the need for family-based labor on the farm.

Cross-national patterns of intergenerational continuities in childbearing in developed countries

Earlier work has shown that the association between the fertility of parents and the fertility of children has become stronger over time in some societies. This article updates and broadens the geographic coverage to assess the magnitude of intergenerational continuities in childbearing in developed and middle-income societies using data for 46 populations from 28 developed countries drawn from a number of recent large-scale survey programs. Robust positive intergenerational fertility correlations are found across these countries into the most recent period, and although there is no indication that the strength of the relationship is declining, the increasing trend does not appear to be continuing.

Differences in intergenerational fertility associations by sex and race in Saba, Dutch Caribbean, 1876-2004

This study examines the intergenerational transmission of fertility behavior in Saba, Dutch Caribbean from 1876 to 2004 using reconstituted genealogies. Pearson product-moment correlation coefficients of several fertility measures and event-history models of age at first birth are used to explore relationships between the fertility of mothers and their children. The strength of intergenerational fertility ties varies by race and gender. Individuals that are better positioned to realize their fertility preferences have the strongest intergenerational associations, while individuals with the most limited reproductive options have the weakest intergenerational associations. This evidence supports hypotheses that posit the intergenerational transmission of attitudes, goals, and behaviors and the ability to act on those preferences as drivers of the presence or magnitude of links between the fertility of parents and their children.