Double impact: What sibling data can tell us about the long‐term negative effects of parental divorce

Abstract

Most prior research on the adverse consequences of parental divorce has analyzed only one child per family. As a result, it is not known whether the same divorce affects siblings differently. We address this issue by analyzing paired sibling data from the 1994 General Social Survey (GSS) and 1994 Survey of American Families (SAF). Both seemingly unrelated regressions and random effects models are used to study the effect of family background on offspring's educational attainment and marital stability. Parental divorce adversely affects the educational attainment and the probability of divorce of both children within a sibship; in other words, siblings tend to experience the same divorce the same way. However, family structure of origin only accounts for a trivial portion of the shared variance in offspring's educational attainment and marital stability, so parental divorce is only one of many factors determining how offspring fare. These findings were unchanged when controlling for a number of differences both between and within sibships. Also, the negative effects of parental divorce largely do not vary according to respondent characteristics.     

Evaluating indirect genetic effects of siblings using singletons

Estimating effects of parental and sibling genotypes (indirect genetic effects) can provide insight into how the family environment influences phenotypic variation. There is growing molecular genetic evidence for effects of parental phenotypes on their offspring (e.g. parental educational attainment), but the extent to which siblings affect each other is currently unclear. Here we used data from samples of unrelated individuals, without (singletons) and with biological full-siblings (non-singletons), to investigate and estimate sibling effects. Indirect genetic effects of siblings increase (or decrease) the covariance between genetic variation and a phenotype. It follows that differences in genetic association estimates between singletons and non-singletons could indicate indirect genetic effects of siblings if there is no heterogeneity in other sources of genetic association between singletons and non-singletons. We used UK Biobank data to estimate polygenic score (PGS) associations for height, BMI and educational attainment in self-reported singletons (N = 50,143) and non-singletons (N = 328,549). The educational attainment PGS association estimate was 12% larger (95% C.I. 3%, 21%) in the non-singleton sample than in the singleton sample, but the height and BMI PGS associations were consistent. Birth order data suggested that the difference in educational attainment PGS associations was driven by individuals with older siblings rather than firstborns. The relationship between number of siblings and educational attainment PGS associations was non-linear; PGS associations were 24% smaller in individuals with 6 or more siblings compared to the rest of the sample (95% C.I. 11%, 38%). We estimate that a 1 SD increase in sibling educational attainment PGS corresponds to a 0.025 year increase in the index individual’s years in schooling (95% C.I. 0.013, 0.036). Our results suggest that older siblings may influence the educational attainment of younger siblings, adding to the growing evidence that effects of the environment on phenotypic variation partially reflect social effects of germline genetic variation in relatives.     

Gender,family configuration,and the effect of family background on educational attainment

Abstract

A comprehensive model of family influences on educational resemblance of siblings expands the traditional sibling pair model to a full sibship model in order to investigate how gender, gender composition of sibships, and a measure of ordinal position moderate the effect of social origins on educational attainments of siblings. One common family factor is sufficient to explain the variation of educational attainment among brothers and sisters. Although effects of social origin variables on brothers are larger than on sisters, the relative effects of measured social origins are virtually the same among sisters and brothers. The disparity between educational attainments of brothers and sisters persists across sex composition and family size. Ordinal position does not alter the effects of social origins on educational attainment nor does it directly affect educational attainment. Father's and mother's education are equally important for all siblings regardless of birth order, gender composition, and family size.     

Women's childhood experience of parental separation and their subsequent health and socioeconomic status in adulthood

The long term consequences for women of parental divorce and separation in childhood are explored using data from a national, prospective, longitudinal survey. In comparison with women who suffered no parental loss, parental divorce is associated with lower educational attainment and occupational status, poorer mental health, higher alcohol consumption and higher rates of remarriage. Links with earlier signs of emotional disturbance and current levels of stress are explored.     

Effect of number and position of siblings on child and adult outcomes

This paper develops a theoretical model of the effects of family size and birth order on educational attainment and earnings. The parental utility maximization model allows the development of closed-form expressions for the within-family ratios of schooling and earnings. A reduced form demand function for each child's schooling and earnings also can be obtained. Each of these functions depends on the exogenous variables of the price of education divided by the price of parental consumption, parental income, the child's endowment, and the parameters of the utility and the production function. Application of this model to empirical data from the Twin and Adult Offspring Sample confirmed both birth order and family size effects for schooling even when parental age, income, education, and father's religion were controlled. The effects were larger for daughters than sons. The difference in educational attainment between 1st and 5th-born was 0.7 years for males and 1.4 years for females. Family size further reduces parental contribution to college education and encourages working, loans, and scholarships. The earnings data do not display birth order effects once family background and sibship size are controlled.     

Marital Dissolution and Child Educational Outcomes in San Borja,Bolivia

Serial monogamy is likely an adaptive mating strategy for women when the expected future fitness gains with a different partner are greater than expected future fitness with one’s current partner. Using interview data from more than 400 women in San Borja, Bolivia, discrete-time event history analyses and random effects regression analyses were conducted to examine predictors of marital dissolution, separated by remarriage status, and child educational outcomes. Male income was found to be inversely associated with women’s risk of “divorce and remarriage,” whereas female income is positively associated with women’s risk of “divorce, but not remarriage.” Children of women who divorce and remarry tend to have significantly lower educational outcomes than children of married parents, but women with higher incomes are able to buffer their children from the negative educational outcomes of divorce and remarriage. Counter to predictions, there is no evidence that women with kin in the community have a significant difference in likelihood of divorce or a buffering effect of child outcomes. In conclusion, predictors of divorce differ depending on whether the woman goes on to remarry, suggesting that male income may be a better predictor of a serial monogamy strategy whereas female income predicts marital dissolution only. Thus, women who are relatively autonomous because of greater income may not benefit from remarriage.     

Birth order, sibship size, and status in modern Canada

This paper investigates the possibility that birth order affects the degree to which individuals attain higher status. Humans give birth to a variable number of (usually) single offspring spaced one to many years apart, and continue to maintain contact with them for extended periods of time. The continued presence of older siblings, and arrival of younger ones, means that each child is reared in a different family environment. Research findings from the field of behavior genetics suggest that these differences have a significant impact on the development of individual differences between children in the same family. Although no two families are likely to be exactly the same, factors such as birth order remain constant across them, and may have similar influences. The present study examines the relationships between birth order, sibship size, and several variables thought to index future status attainment (status striving) in a random sample of Canadians. Firstborn children appear to be more status oriented than lastborns, and this effect is mediated by sibship size. While firstborn children are unaffected by the number of younger siblings they have, the status ambitions of youngest children decrease the more older siblings they have. Birth order effects on status attainment are not as strong as they are on status ambitions.     

Effect of number and position of siblings on child and adult outcomes

Abstract

In this paper we consider how family size and birth order may affect educational attainment and earnings. Family size may be important because if more children have to share parental financial, emotional, and time resources, each child may get less. Birth order may be important because of differences in endowments, parental resources over the life cycle, or parental preferences. We demonstrate how these different factors interact in a particular model.

Empirically we find both birth‐order and family‐size effects for schooling even when controlling for parental age, income, and education and father's religion. These effects are bigger for daughters than sons. Using the same controls, we do not find statistically significant family‐size or birth‐order effects for the In of earnings in a relatively young sample. We also present equations for how college was financed. Family size cuts down parental contribution per child and encourages working, scholarship, and loans. Results differ somewhat for sons and daughters.     

Patterns of child fosterage in rural northern Thailand

Evolutionary theory guides an investigation of foster parent selection in two northern Thai villages with different biosocial environments: one village has high levels of labour migration and divorce, and growing numbers of parental death due to HIV/AIDS, while the other village has lower migration, divorce and parental mortality levels. Focus groups examine mothers' and fathers' motivations and ideals regarding foster caretaker selection, and quantitative family surveys examine real fostering outcomes: specifically, the laterality (matrilateral versus patrilateral) and genetic distance of the foster caretakers of all ever-fostered children in these two villages. As predicted, in environments of high marital stability and paternity certainty, parents seem to prefer close genetic kin from either side as foster parents for their children. In low marital stability and paternity certainty environments, parents trust their own lateral kin, regardless of genetic distance, over close genetic kin from the other side. The striking exception to this pattern, however, occurs in the case of parental death, in which case children are fostered to the deceased parent's kin, regardless of the child's sex or other factors. In general, the foster parents for girls are selected with more care, reflecting the daughter/female preference expected in traditionally matrilineal, matrilocal societies. An ordered decision-making pathway for foster parent selection is proposed, taking into consideration the key factors of (a) the circumstances driving the fostering decision, (b) the gender of the child, (c) the gender of the key decision-making parent, and (d) the degree of marital and population fluidity (and subsequent, paternity certainty) in the village.     

Further investigations of educational and occupational attainment in the Hawaii family study of cognition

Abstract

Associations of measures of grandparental status, parental status, cognitive abilities, and personality, and own cognitive abilities and personality with educational and occupational attainment are reported for 249 offspring, now 25 years or older, from the Hawaii Family Study of Cognition (HFSC). In general, across two ethnic groups (Americans of European ancestry (AEA) and Americans of Japanese ancestry (AJA)), the data suggest that family background had a relatively trivial influence, own cognitive abilities (particularly verbal ability and general intelligence) substantial influence, and own personality some influence on the educational and occupational attainment of males, while family background had a far more substantial influence than own ability on the attainment of females. Educational attainment was generally found to be substantially predictive of occupational attainment. Hierarchal multiple regression analyses were conducted to assess the influence of parents’ abilities over and above grandparental status and the influence of offsprings’ abilities over and above parental status and abilities on their respective educational and occupational attainments. These analyses also indicated that family background was a much greater influence than own ability on the attainment of AEA female parents and both AEA and AJA female offspring. These findings for female offspring were further confirmed by analyses of parent‐offspring and within‐sibship differences in attainment.     

The survivance of French Canadians in New England (1865–1930): History,geography and demography as destiny*

This article analyses the Urban Poverty and Family Life Survey of Chicago and an urban subsample of the National Survey of Families and Households to examine race and ethnic variation in the occurrence and consequences of birth versus marriage pathways to family formation. Results based on multiple‐decrement life table analysis and multi‐variate life table regression analysis reveal strong race and poverty effects on pathways to family formation, but Hispanic origin does not systematically influence the odds that women will enter family life via marriage versus birth. We show stronger race effects on pathways to family formation for the Chicago sample owing to the much higher incidence of teen parenting among black inner‐city residents. Results also suggest lasting economic consequences of non‐marital fertility, irrespective of whether women eventually marry or divorce subsequent to a premarital birth.     

Parental nonemployment in childhood and children’s health later in life

While the effects of joblessness on the health of the non-employed are well-documented, its long-term spillover consequences on the health of their relatives, especially children, remain poorly understood. This research explores the long-term associations of parental nonemployment spells experienced during early, mid and late childhood on children’s mental and physical health. The analysis exploits data drawn from the British Household Panel Survey (BHPS) and the UK Household Longitudinal Study (UKHLS), linking detailed parental socioeconomic information with their children between the years 1993 and 2013. This paper employs a Correlated Random Effects (CRE) probit model that allows accounting for unobserved heterogeneity as well as a non-linear Generalized Estimating Equations (GEE) random effects estimator accounting in addition for the dependency structure of the data. Results indicate that experiencing parental nonemployment during early and late childhood has a negative association on the children’s likelihood of suffering from long-standing illnesses later in life, while experiencing parental nonemployment during middle childhood negatively affects the young adult’s mental health. Moreover, experiencing parental nonemployment during late childhood increases the probability of both reporting poor or fair self-assessed health and the likelihood of consuming prescribed medicines in early adulthood. However, there seems to be a considerable effect heterogeneity by family socioeconomic status, parents’ gender, and frequencies of parental nonemployment spells. Current adulthood circumstances, such as level of educational attainment, job situation and household demographics, are used to explore the potential mechanisms affecting results. These findings may help policymakers shape appropriate responses to mitigate the psychological and physical burden derived from parental nonemployment, especially among already disadvantaged households.     

Models of parent-offspring conflict. V. Effects of the behaviour of the two parents

In the absence of any parent-offspring conflict, the total parental investment per offspring should be less when two parents collaborate in caring for the offspring than when only one parent invests. This does not necessarily mean that offspring fare less well when both parents invest. The ‘ideal’ amount of parental investment for an offspring to take is always greater than is ‘ideal’ for the parent to allocate (Trivers 1974). The offspring's optimum is higher if the offspring's action affects the reproductive success of only one parent and lower if both parents are affected (e.g. two-parent investment, or lifelong monogamy). The difference between the parental optimum and the offspring optimum depends on the mating system and on the form of conflict (between successive broods, or within broods), and prescribes a ‘conflict range’. The extent of conflict cannot be deduced solely from a knowledge of the average relatedness between siblings. The conflict is likely to be resolved by an ESS in which intermediate (compromise) levels of investment are paid out to offspring, which nevertheless continue to make costly demands for yet more investment. The degree of conflict can be measured by the extent to which offspring subject their parents to aggressive demands for extra investment, and is likely to be greater when two parents collaborate equally over investment than when only one parent invests. When only one parent invests, conflict is higher if sibling-competition is between siblings in the same broods (intra-brood) than when it is between progeny in successive broods (inter-brood). However, the reverse will tend to be the case when both parents invest equally.     

Children's health and their mothers’ risk of divorce or separation

Abstract

The purpose of this study is to determine how children's health conditions are related to their mothers’ risk of divorce or separation. The study is based on data from over 7,000 children born to once‐married mothers identified in the 1988 Child Health Supplement to the National Health Interview Survey. The effects of 15 childhood health conditions on the mothers’ risk of divorce are estimated with Cox's proportional hazard models. Controlling for demographic, marital, and reproductive measures, we find that mothers’ prospects for divorce are affected both positively or negatively by their children's health status, depending on the type of childhood condition and, in the case of low birth weight children, timing within the marriage. Women whose children have congenital heart disease, cerebral palsy, are blind, or had low birth weight appear to have higher risks of marital disruption than mothers of healthy children. In contrast, mothers whose children have migraines, learning disabilities, respiratory allergies, missing/deformed digits or limbs, or asthma have somewhat lower rates of divorce.     

Genetic nurture in educational attainment

Health is strongly and positively correlated with education, which is one of many reasons to better understand the determinants of education. In this paper, we test for a specific type of family influence on education: genetic nurture. Specifically, we test whether a person’s educational attainment is correlated with their sibling’s polygenic score (PGS) for education, controlling for their own PGS. Models estimated using data from the National Longitudinal Survey of Adolescent to Adult Health (Add Health) yield strong evidence of genetic nurture; a two-standard deviation increase in a sibling’s genetic predisposition to higher education is associated with a 13.6% point increase in the probability that the respondent has a college degree. Evidence of genetic nurture is robust to alternative measures of educational attainment and different measures of the polygenic score. An exploration of mechanisms suggests that omission of parental PGS explains no more than half of the estimated effect, and that the magnitude of the genetic nurture varies with the characteristics of the sibling.     

Long-term effects of early parental loss due to divorce on the HPA axis

We investigated the long-term effects of divorce and early separation from one parent on HPA axis reactivity, in young adults without psychopathology. Participants were 44 young subjects, 22 whose parents divorced before they reached age 10, and 22 controls. Psychiatric symptomatology was measured with the Brief Symptom Inventory (BSI), family perceived stress by the Dyadic Adjustment Scale (DAS), and bonding by the Parental Bonding Instrument (PBI). Assessment of HPA axis function included baseline morning cortisol and ACTH and cortisol response to a CRH stimulation test. No baseline or stimulated group differences were observed for ACTH. Cortisol levels were consistently but insignificantly lower in the divorce group throughout the CRH stimulation reaching statistical significance only at 5 min (p<0.03). Group by time effect reached a trend level (p<0.06). A correlation was found between psychiatric symptomatology and PBI scores; however, both parameters did not correlate with HPA axis activity. A significant correlation was found between DAS scores and ACTH. A regression model revealed a contributing effect for both family stress and child-parent bonding to stimulated ACTH levels. These preliminary findings suggest that even in the absence of adult psychopathology, a history of childhood separation from one parent due to divorce may lead to detectable, albeit mild, long-term alterations in HPA axis activity. Furthermore, they suggest that level of stress at home and parental bonding are important determinants of this effect. It is likely that divorce has significant and sustained effects on children's HPA axis only in the context of a traumatic separation.     

Differential reproduction: Its relation to IQ test score,education, and occupation

Abstract

The correlations among IQ test score, educational attainment rating, socioeconomic status, total number of children in the family of origin, total number of offspring in completed families, and mean age at birth of live‐born children are examined for a representative sample of the Minnesota white population. Natural selection appears to be favoring an increase in the mean IQ score in the sample, or at least there is no evidence for a decrease. The data show positive marital assortment for IQ score and for educational attainment. Four estimates of the heritability of the phenotype “IQ test score” coincide well with each other. The value of h² estimated from parent‐children regression is 0.631; from a weighted regression of children's scores on the score of the father alone, it is 0.668 and on the score of the mother alone, it is 0.654. The estimate from the intra‐class correlation of full siblings is 0.666.     

Unbiased application of the transmission/disequilibrium test to multilocus haplotypes

When the transmission/disequilibrium test (TDT) is applied to multilocus haplotypes, a bias may be introduced in some families for which both parents have the same heterozygous genotype at some locus. The bias occurs because haplotypes can only be deduced from certain offspring, with the result that the transmissions of the two parental haplotypes are not independent. We obtain an unbiased TDT for individual haplotypes by calculating the correct variance for the transmission count within a family, using information from multiple siblings if they are available. An existing correction for dependence between siblings in the presence of linkage is retained. To obtain an unbiased multihaplotype TDT, we must either count transmissions from one randomly chosen parent or count all transmissions and estimate the significance level empirically. Alternatively, we may use missing-data techniques to estimate uncertain haplotypes, but these methods are not robust to population stratification. An illustration using data from the insulin-gene region in type 1 diabetes shows that the validity and power of the TDT may vary by an order of magnitude, depending on the method of analysis.     

Divorce in the socially monogamous zebra finch: Hormonal mechanisms and reproductive consequences

Up to 80% of all bird species are socially monogamous. Divorce (switching partners) or pair disruption (due to the death of a partner) has been associated with decreased reproductive success, suggesting social monogamy is a strategy that may maximize fitness via coordination between partners. Previous studies have demonstrated the effects of divorce and pair disruption on immediate reproductive success. Here, we used a paired experimental design in the zebra finch (Taeniopygia guttata) to examine the hormonal mechanisms that modulate parental behavior and reproductive success in response to a partnership change (hereafter divorce). Specifically, we examined the effects of divorce on the avian stress hormone corticosterone (CORT) in both parents and nestlings, parental behaviors (incubation and nestling provisioning), prolactin (PRL), and reproductive success. We found that divorce resulted in delayed clutch initiation, reduced clutch mass, and an increase in nestling CORT response to a standardized stressor. These effects on reproductive investment and chick CORT response were not clearly determined by parental endocrine responses. Divorce had no effect on the level of parental CORT. PRL levels were highly correlated within a pair regardless of treatment, were negatively related to the investment that males made in incubation, and increased in experimental males as a result of pair disruption. This study demonstrates the fundamental impact which divorce has not only on reproduction, but also the physiological stress responses of offspring and suggests that in socially monogamous animals the maintenance of a stable partnership over time could be advantageous for long term fitness.     

Marital instability among British Pakistanis: transnationality,conjugalities and Islam

This article offers insights into the dynamics underlying an increase in marital instability in British Pakistani families, thus challenging stereotypes of British South Asian populations as representing ‘old-fashioned’ families, with their lower rates of divorce in contrast with the wider British population. In addition to problems of compatibility, domestic violence and infidelity, we explore dynamics that may be more specific to the British Pakistani population, namely the transnational nature of many marriages, attitudes to parental involvement in arranging marriages, and the place of Islam. We suggest that, while arranged marriages were conventionally seen as safer than love marriages, both young people and their parents may now be viewing arranged marriages as riskier. In an arranged marriage that brings family approval but not personal fulfilment, young people are increasingly supported to divorce and remarry, with a greater degree of personal say in spouse selection.