Father Absence and Accelerated Reproductive Development in Non-Hispanic White Women in the United States

The nature of nurture: Darwinian and mendelian perspectives

Two perspectives on the nature of nurture are reviewed, one Mendelian and the other Darwinian, in an effort to draw links between the two and, thereby, integrate them in a developmental modern synthesis, mirroring the one that took place in biology early in the last century. Thus, the heritability of environmental measures and gene-X-environment interaction are discussed with respect to Mendelian nature before turning attention to Darwinian nature and thus the development of reproductive strategies and differential susceptibility to environmental influences. Conclusions are drawn with respect to both frameworks indicating that it is time to abandon the biology-is-destiny resistance to both approaches to studying and thinking about development, especially when it comes to the nature of nurture. Implications for the future development of the field of developmental psychopathology are highlighted.

Separating Scarring Effect and Selection of Early-Life Exposures With Genetic Data

Causal life course research examining consequences of early-life exposures has largely relied on associations between early-life environments and later-life outcomes using exogenous environmental shocks. Nonetheless, even with (quasi-)randomized early-life exposures, these associations may reflect not only causation ("scarring") but also selection (i.e., which members are included in data assessing later life). Investigating this selection and its impacts on estimated effects of early-life conditions has, however, often been ignored because of a lack of pre-exposure data. This study proposes an approach for assessing and correcting selection, separately from scarring, using genetic measurements. Because genetic measurements are determined at the time of conception, any associations with early-life exposures should be interpreted as selection. Using data from the UK Biobank, we find that in utero exposure to a higher area-level infant mortality rate is associated with genetic predispositions correlated with better educational attainment and health. These findings point to the direction and magnitude of selection from this exposure. Corrections for this selection in examinations of effects of exposure on later educational attainment suggest underestimates of 26-74%; effects on other life course outcomes also vary across selection correction methods.

Testing Environmental Effects on Age at Menarche and Sexual Debut within a Genetically Informative Twin Design

Life-history-derived models of female sexual development propose menarche timing as a key regulatory mechanism driving subsequent sexual behavior. The current research utilized a twin subsample of the National Longitudinal Study of Adolescent to Adult Health (Add Health; n = 514) to evaluate environmental effects on timings of menarche and sexual debut, as well as address potential confounding of these effects within a genetically informative design. Results show mixed support for each life history model and provide little evidence rearing environment is important in the etiology of individual differences in age at menarche. This research calls into question the underlying assumptions of life-history-derived models of sexual development and highlights the need for more behavior genetic research in this area.

Father absence and pubertal timing in Korean boys and girls

Background and objectives

Pubertal timing is a key life history trait with long-term health consequences in both sexes. Evolutionary theory has guided extensive research on developmental influences, in particular growing up without a father, on earlier menarche. Far less is known whether a similar relationship exists for boys, especially beyond western contexts. We used longitudinal data from the nationally representative sample of Korean adolescents, which provided us with a unique opportunity for studying male puberty using a hitherto underutilized biomarker: age at first nocturnal ejaculation.

Methodology

We pre-registered and tested a prediction that growing up in father-absent households is associated with earlier puberty in both sexes. Large sample size (>6000) allowed testing the effect of father absence, which remains relatively uncommon in Korea, while adjusting for potential confounders using Cox proportional-hazard models.

Results

Self-reported age at first nocturnal ejaculation was on average 13.8 years, falling within the range known from other societies. Unlike previous findings mostly for white girls, we did not find evidence that Korean girls in father-absent households had a younger age at menarche. Boys in father-absent households reported having their first nocturnal ejaculation 3 months earlier on average, and the difference was evident before age 14.

Conclusion and implications

The association between father absence and pubertal timing appears sex- and age-dependent, and these differences may further interact with cultural norms regarding gender roles. Our study also highlights the utility of the recalled age of first ejaculation for male puberty research, which has lagged in both evolutionary biology and medicine.

The influence of harshness and unpredictability on female sexual development: Addressing gene-environment interplay using a polygenic score

Recent developments in the application life history theory to human development indicate two fundamental dimension of the early environment - harshness and unpredictability - are key regulators life history strategies. Few studies have examined the manner with which these dimensions influence development, though age at menarche (AAM) and age at first sexual intercourse have been proposed as possible mechanisms among women. Data from the Avon Longitudinal Study of Parents and Children (N = 3,645) were used to examine direct and indirect effects of harshness (financial difficulties) and unpredictability (paternal transitions) on lifetime and past year sexual partners during adolescence and young adulthood. Genetic confounding was addressed using an AAM polygenic score (PGS) and potential gene-by-environment interactions were also evaluated using the PGS. Path model results showed only harshness was directly related to AAM. Harshness, unpredictability, and AAM were indirectly related to lifetime and past year sexual partner number via age at first sexual intercourse. The PGS did not account for any of the associations and no significant interactions were detected. Implications of these results for developmental models derived from life history theory are discussed as well as the role of PGSs in gene-environment interplay research.

Family environmental antecedents of pubertal timing in girls and boys: A review and open questions

Across nonhuman species, pubertal timing is affected by the social environment, with consequences for reproductive success and behavior. In human beings, variations in pubertal timing have not been systematically examined in relation to social environmental antecedents, although their psychological consequences are well documented. This paper focuses on links in human beings between pubertal timing and the childhood social environment, with several sections: A review of studies relating pubertal timing to the family context, a key aspect of the social environment; challenges in studying the issue; and opportunities for future work that takes advantage of and creates links with evidence in other species. The review shows that pubertal timing in girls is accelerated by adversity in aspects of the early family social context, with effects small in size; data in boys are not sufficient to enable conclusions. Inferences from existing studies are limited by variations in conceptualizations and measurement of relevant aspects of puberty and of the family social environment, and by methodological issues (e.g., reliance on existing data, use of retrospective reports, nonrandom missing data). Open questions remain about the nature, mechanisms, and specificity of the links between early family social environment and pubertal timing (e.g., form of associations, consideration of absence of positive experiences, role of timing of exposure). Animal studies provide a useful guide for addressing these questions, by delineating potential hormonal mechanisms that underlie links among social context, pubertal timing, and behavior, and encouraging attention to aspects of the social environment outside the family, especially peers.

Has demography witnessed a data revolution? Promises and pitfalls of a changing data ecosystem

Over the past 25 years, technological improvements that have made the collection, transmission, storage, and analysis of data significantly easier and more cost efficient have ushered in what has been described as the 'big data' era or the 'data revolution'. In the social sciences context, the data revolution has often been characterized in terms of increased volume and variety of data, and much excitement has focused on the growing opportunity to repurpose data that are the by-products of the digitalization of social life for research. However, many features of the data revolution are not new for demographers, who have long used large-scale population data and been accustomed to repurposing imperfect data not originally collected for research. Nevertheless, I argue that demography, too, has been affected by the data revolution, and the data ecosystem for demographic research has been significantly enriched. These developments have occurred across two dimensions. The first involves the augmented granularity, variety, and opportunities for linkage that have bolstered the capabilities of 'old' big population data sources, such as censuses, administrative data, and surveys. The second involves the growing interest in and use of 'new' big data sources, such as 'digital traces' generated through internet and mobile phone use, and related to this, the emergence of 'digital demography'. These developments have enabled new opportunities and offer much promise moving forward, but they also raise important ethical, technical, and conceptual challenges for the field.

Achieved educational attainment, inherited genetic endowment for education, and obesity

This study investigates two sources of education effects on obesity - achieved educational attainment and inherited genetic endowment for education. In doing so, we accomplish two goals. First, we assess the role of genetic confounding in the association between education and health. Second, we consider the heterogeneity in the extent to which genetic potential for education is realized, and we examine its impact on obesity. Data come from the National Longitudinal Study of Adolescent to Adult Health. Using a polygenic score approach, we find that, net of genetic confounding, holding a college degree is associated with a lower likelihood of obesity. Moreover, among individuals who hold a college degree, those with a high education polygenic score (a greater genetic propensity to succeed in education) are less likely to be obese than those with a relatively low education polygenic score. However, when individuals with a high education polygenic score do not have a college degree, their risk of obesity is similar to that of non-college-educated individuals with a low education polygenic score, suggesting that the effect of genetic endowment for education on obesity is conditional on college education.

Neurobiological mechanisms of early life adversity, blunted stress reactivity and risk for addiction

Blunted stress reactivity resulting from early exposure to stress during childhood and adolescence may increase vulnerability to addiction. Early life adversity (ELA) affects brain structure and function and results in blunted stress axis reactivity. In this review, we focus on the underlying neurobiological mechanisms associated with a blunted response to stress, ELA, and risk for addictive disorders. ELA and blunted reactivity are accompanied by unstable mood regulation, impulsive behaviors, and reduced cognitive function. Neuroimaging studies reveal cortical and subcortical changes in persons exposed to ELA and those who have a genetic disposition for addiction. We propose a model in which blunted stress reactivity may be a marker of risk for addiction through an altered motivational and behavioral reactivity to stress that contribute to disinhibited behavioral reactivity and impulsivity leading in turn to increased vulnerability for substance use. Evidence supporting this hypothesis in the context of substance use initiation, maintenance, and risk for relapse is presented. The effects of ELA on persons at risk for addiction may lead to early experimentation with drugs of abuse. Early adoption of drug intake may alter neuroregulation in such vulnerable persons leading to a permanent dysregulation of motivational responses consistent with dependence. This article is part of the special issue on 'Vulnerabilities to Substance Abuse'.

A polygenic score for age-at-first-birth predicts disinhibition

BACKGROUND

A recent genome-wide association study identified molecular-genetic associations with age-at-first-birth. However, the meaning of these genetic discoveries is unclear. Drawing on evidence linking early pregnancy with disinhibitory behavior, we tested the hypothesis that genetic discoveries for age-at-first-birth predict disinhibition.

METHODS

We included participants with genotype data from the two-decade-long Environmental Risk (E-Risk) Study (N = 1,999) and the four-decade-long Dunedin Study (N = 918). We calculated a genome-wide polygenic score for age-at-first-birth and tested whether it was associated with a range of disinhibitory outcomes across the life course, including low childhood self-control; risk for externalizing psychopathology; officially recorded criminal offending; substance dependence; informant reports of disinhibitory problems; and number of lifetime sexual partners. We further tested whether associations were attributable to accelerated pubertal maturation.

RESULTS

In both cohorts, the age-at-first-birth polygenic score predicted low childhood self-control, externalizing psychopathology, officially recorded criminal offending, substance dependence, and number of sexual partners. Associations were modest, but robust across replication. Childhood disinhibition partly mediated associations between the polygenic score and reproductive behaviors. In contrast, associations were not attributable to accelerated pubertal timing.

CONCLUSIONS

Genomic discoveries for age-at-first-birth are about more than reproductive biology: They provide insight into the disinhibitory traits and behaviors that accompany early parenthood. Age-at-first-birth is a useful proxy phenotype for researchers interested in disinhibition. Further, interventions that improve self-regulation abilities may benefit young parents and their children.

Father absence, age at menarche, and genetic confounding: A replication and extension using a polygenic score

Father absence has a small but robust association with earlier age at menarche (AAM), likely reflecting both genetic confounding and an environmental influence on life history strategy development. Studies that have attempted to disambiguate genetic versus environmental contributions to this association have shown conflicting findings, though genomic-based studies have begun to establish the role of gene-environment interplay in the father absence/AAM literature. The purpose of this study was to replicate and extend prior genomic work using the Avon Longitudinal Study of Parents and Children (ALSPAC), a prospective longitudinal cohort study (N = 2,685), by (a) testing if an AAM polygenic score (PGS) could account for the father absence/AAM association, (b) replicating G×E research on lin-28 homolog B (LIN28B) variation and father absence, and (c) testing the G×E hypothesis using the PGS. Results showed that the PGS could not explain the father absence/AAM association and there was no interaction between father absence and the PGS. Findings using LIN28B largely replicated prior work that showed LIN28B variants predicted later AAM in father-present girls, but this AAM-delaying effect was absent or reversed in father-absent girls. Findings are discussed in terms genetic confounding, the unique biological role of LIN28B, and using PGSs for G×E tests.

GENETICS IN ENDOCRINOLOGY: Genetic etiologies of central precocious puberty and the role of imprinted genes

Pubertal timing is regulated by the complex interplay of genetic, environmental, nutritional and epigenetic factors. Criteria for determining normal pubertal timing, and thus the definition of precocious puberty, have evolved based on published population studies. The significance of the genetic influence on pubertal timing is supported by familial pubertal timing and twin studies. In contrast to the many monogenic causes associated with hypogonadotropic hypogonadism, only four monogenic causes of central precocious puberty (CPP) have been described. Loss-of-function mutations in Makorin Ring Finger Protein 3(MKRN3), a maternally imprinted gene on chromosome 15 within the Prader-Willi syndrome locus, are the most common identified genetic cause of CPP. More recently, several mutations in a second maternally imprinted gene, Delta-like noncanonical Notch ligand 1 (DLK1), have also been associated with CPP. Polymorphisms in both genes have also been associated with the age of menarche in genome-wide association studies. Mutations in the genes encoding kisspeptin (KISS1) and its receptor (KISS1R), potent activators of GnRH secretion, have also been described in association with CPP, but remain rare monogenic causes. CPP has both short- and long-term health implications for children, highlighting the importance of understanding the mechanisms contributing to early puberty. Additionally, given the role of mutations in the imprinted genes MKRN3 and DLK1 in pubertal timing, other imprinted candidate genes should be considered for a role in puberty initiation.

Association of Early-Life Adversity With Measures of Accelerated Biological Aging Among Children in China

IMPORTANCE

A growing body of literature suggests that exposure to early-life adversity (ELA) is associated with accelerated biological aging, offering 1 mechanism through which ELA may be associated with an increased risk for age-related disease. These investigations, however, have been predominantly cross-sectional and focused on adults and females.

OBJECTIVE

To evaluate associations of threat-related (ie, physical abuse) and deprivation-related (ie, emotional neglect) ELA exposure with cellular and reproductive strategy metrics of biological aging among boys and girls with specific genetic backgrounds around the period of pubertal onset.

DESIGN, SETTING, AND PARTICIPANTS

In this cohort study, 997 boys and girls in grade 1 to grade 3 from 3 large elementary schools were recruited from Bengbu, Anhui Province, China, and were followed up from March 21, 2016 (baseline; wave 1), for 4 consecutive years, through March 25, 2019.

MAIN OUTCOMES AND MEASURES

The outcome was accelerated biological aging in both cellular and reproductive strategy metrics: telomere attrition and age at thelarche (for girls) and testicular maturation (for boys). Multi-informant assessment of exposure to threat-related and deprivation-related ELA was done at baseline (wave 1) and 1-year follow-up (wave 2). The polygenic risk score (PRS) was computed based on 17 single-nucleotide variations for early pubertal timing.

RESULTS

Of the 997 participants (579 girls [58.1%]; mean [SD] age at baseline, 8.0 [0.8] years), 550 (55.2%) reported exposure to threat-related ELA and 443 (44.4%) reported exposure to deprivation-related ELA. Threat-related ELA was associated with onset of thelarche 2.6 months earlier and deprivation-related ELA with onset of thelarche 3.3 months earlier in exposed girls than in unexposed peers; these associations were observed only among girls with a low PRS. Among boys, a similar pattern was found. Threat-related ELA was associated with testicular volume of 4 mL or more 1.4 months earlier and deprivation-related ELA was associated with testicular volume of 4 mL or more 2.3 months earlier than in unexposed peers but only among those with a low PRS. Boys and girls with greater exposure to threats showed a significantly higher percentage of telomere length change during 1-year follow-up, but only among those with low PRS (boys: β = 1.50; 95% CI, 0.80-2.21; P < .001; girls: β = 2.40; 95% CI, 1.78-3.05; P < .001) and moderate PRS (boys: β = 1.09; 95% CI, 0.43-1.75; P = .001; and girls: β = 1.27; 95% CI, 0.77-1.77; P < .001). No associations of deprivation-related ELA with percentage of telomere length change were found.

CONCLUSIONS AND RELEVANCE

This study suggests that the accelerating association of ELA with biological aging might occur at an earlier age and in a genetic background-dependent and dimension-specific manner.

Unravelling the role of epigenetics in reproductive adaptations to early-life environment

Reproductive function adjusts in response to environmental conditions in order to optimize success. In humans, this plasticity includes age of pubertal onset, hormone levels and age at menopause. These reproductive characteristics vary across populations with distinct lifestyles and following specific childhood events, and point to a role for the early-life environment in shaping adult reproductive trajectories. Epigenetic mechanisms respond to external signals, exert long-term effects on gene expression and have been shown in animal and cellular studies to regulate normal reproductive function, strongly implicating their role in these adaptations. Moreover, human cohort data have revealed differential DNA methylation signatures in proxy tissues that are associated with reproductive phenotypic variation, although the cause-effect relationships are difficult to discern, calling for additional complementary approaches to establish functionality. In this Review, we summarize how adult reproductive function can be shaped by childhood events. We discuss why the influence of the childhood environment on adult reproductive function is an important consideration in understanding how reproduction is regulated and necessitates consideration by clinicians treating women with diverse life histories. The resolution of the molecular mechanisms responsible for human reproductive plasticity could also lead to new approaches for intervention by targeting these epigenetic modifications.

Biological aging in childhood and adolescence following experiences of threat and deprivation: A systematic review and meta-analysis

Life history theory argues that exposure to early life adversity (ELA) accelerates development, although existing evidence for this varies. We present a meta-analysis and systematic review testing the hypothesis that ELA involving threat (e.g., violence exposure) will be associated with accelerated biological aging across multiple metrics, whereas exposure to deprivation (e.g., neglect, institutional rearing) and low-socioeconomic status (SES) will not. We meta-analyze 54 studies (n = 116,010) examining associations of ELA with pubertal timing and cellular aging (telomere length and DNA methylation age), systematically review 25 studies (n = 3,253) examining ELA and neural markers of accelerated development (cortical thickness and amygdala-prefrontal cortex functional connectivity) and evaluate whether associations of ELA with biological aging vary according to the nature of adversity experienced. ELA overall was associated with accelerated pubertal timing (d = -0.10) and cellular aging (d = -0.21), but these associations varied by adversity type. Moderator analysis revealed that ELA characterized by threat was associated with accelerated pubertal development (d = -0.26) and accelerated cellular aging (d = -0.43), but deprivation and SES were unrelated to accelerated development. Systematic review revealed associations between ELA and accelerated cortical thinning, with threat-related ELA consistently associated with thinning in ventromedial prefrontal cortex, and deprivation and SES associated with thinning in frontoparietal, default, and visual networks. There was no consistent association of ELA with amygdala-PFC connectivity. These findings suggest specificity in the types of early environmental experiences associated with accelerated biological aging and highlight the importance of evaluating how accelerated aging contributes to health disparities and whether this process can be mitigated through early intervention. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Neighborhood Disorder, Family Functioning, and Risky Sexual Behaviors in Adolescence

Adolescent risky sexual behaviors can result in negative consequences such as sexually transmitted infection. However, much research effort has been placed on understanding individual characteristics, rather than the role of neighborhood environment. This study addressed the prospective effects of neighborhood and family functioning in preadolescence on risky sexual behaviors. Participants included 4179 youth (Mage = 11.01 years, range 8.64-13.83; 51% female) and their caregivers. Using objective and self-reported measures of neighborhood and family functioning, results from multilevel regression analyses indicated that youth residing in disordered neighborhoods or had poorer family functioning in preadolescence were more likely to initiate sexual intercourse at younger ages 5 years later. Specifically, neighborhood poverty and decay were linked to early sexual initiation, whereas neighborhood social and family processes were protective against early sexual initiation. Males were more likely to engage in risky sexual behaviors in neighborhoods with greater poverty or decay; neighborhood poverty was linked with sexual initiation in White but not African American youth. Finally, parental monitoring moderated relationships between neighborhood social resources and contraceptive use, with neighborhood social resources linked with greater contraceptive use at low levels of parental monitoring, but lower contraceptive use at high levels of parental monitoring. These findings underscore the importance of neighborhood and family contexts in adolescents' risky sexual behavior, suggesting that males and White youth are more vulnerable to the effects of neighborhood poverty and that more research is needed on the possible counterproductive function of parental monitoring in neighborhoods with greater social resources.

Parents of early-maturing girls die younger

According to the life-history theory, rates of sexual maturation have coevolved with mortality rates so that individuals who mature faster tend to die younger. We used two data sets, providing different markers for the speed of pubertal development to test whether rates of sexual maturation of women predict the age at death of their parents. In the data set of Estonian schoolgirls born between 1936 and 1961, the rate of breast development predicted lifespan of both mothers and fathers (irrespectively of their socio-economic position), so that parents of rapidly maturing girls died at younger age. This finding supports the view that fast maturation rates in humans have coevolved with short lifespans and that such trade-offs can be detected as intergenerational phenotypic correlations in modern populations. Menarcheal age of participants of Estonian Biobank (born between 1925 and 1996) did not predict the age of death of their mothers; however, it did predict survival of their fathers, but only in environment where the genetic variation is exposed (families where at least one parent had tertiary education). In such families (where girls also matured 0.2-0.4 years earlier than in poorly educated families), 1-year delay in daughter's menarche corresponded to 9% lower hazard of father's death. Heritability of menarcheal age was also highest in well-educated families. The latter findings are consistent with the idea that genetic differences in the rate of pubertal maturation may be expressed most clearly in well-off families because in such families, the contribution of environmental variance to total phenotypic variance in menarcheal age is smallest. Our findings suggest that with global improvement and equalization of growth conditions, reductions of environmental variation in the rate of maturation increasingly expose the genetic differences in menarcheal age to selection. Under such conditions, selection on menarcheal age has a potential to affect the evolution of lifespan.

Cross-cultural evidence does not support universal acceleration of puberty in father-absent households

Father absence in early life has been shown to be associated with accelerated reproductive development in girls. Evolutionary social scientists have proposed several adaptive hypotheses for this finding. Though there is variation in the detail of these hypotheses, they all assume that family environment in early life influences the development of life-history strategy, and, broadly, that early reproductive development is an adaptive response to father absence. Empirical evidence to support these hypotheses, however, has been derived from WEIRD (Western, Educated, Industrialized, Rich and Democratic) populations. Data from a much broader range of human societies are necessary in order to properly test adaptive hypotheses. Here, we review the empirical literature on father absence and puberty in both sexes, focusing on recent studies that have tested this association beyond the WEIRD world. We find that relationships between father absence and age at puberty are more varied in contexts beyond WEIRD societies, and when relationships beyond the father-daughter dyad are considered. This has implications for our understanding of how early-life environment is linked to life-history strategies, and for our understanding of pathways to adult health outcomes, given that early reproductive development may be linked to negative health outcomes in later life This article is part of the theme issue 'Developing differences: early-life effects and evolutionary medicine'.

Early-Life Adversity Accelerates Child and Adolescent Development

Most developmental work regards adverse developmental experiences as forces that undermine well-being. Here, I present an alternative—or complementary—view, summarizing recent evidence on puberty, endocrinology, cellular aging, and brain connectivity that collectively reveals developmental acceleration in response to contextual adversity. Findings are cast in evolutionary-developmental terms, highlighting the trade-off between accelerated aging and (a) increased morbidity and (b) premature mortality.

Phenotypic Annotation: Using Polygenic Scores to Translate Discoveries From Genome-Wide Association Studies From the Top Down

Genome-wide association studies (GWASs) have identified specific genetic variants associated with complex human traits and behaviors, such as educational attainment, mental disorders, and personality. However, small effect sizes for individual variants, uncertainty regarding the biological function of discovered genotypes, and potential "outside-the-skin" environmental mechanisms leave a translational gulf between GWAS results and scientific understanding that will improve human health and well-being. We propose a set of social, behavioral, and brain-science research activities that map discovered genotypes to neural, developmental, and social mechanisms and call this research program phenotypic annotation. Phenotypic annotation involves (a) elaborating the nomological network surrounding discovered genotypes, (b) shifting focus from individual genes to whole genomes, and (c) testing how discovered genotypes affect life-span development. Phenotypic-annotation research is already advancing the understanding of GWAS discoveries for educational attainment and schizophrenia. We review examples and discuss methodological considerations for psychologists taking up the phenotypic-annotation approach.

Developmental Adaptation to Stress: An Evolutionary Perspective

The assumption that early stress leads to dysregulation and impairment is widespread in developmental science and informs prevailing models (e.g., toxic stress). An alternative evolutionary–developmental approach, which complements the standard emphasis on dysregulation, proposes that early stress may prompt the development of costly but adaptive strategies that promote survival and reproduction under adverse conditions. In this review, we survey this growing theoretical and empirical literature, highlighting recent developments and outstanding questions. We review concepts of adaptive plasticity and conditional adaptation, introduce the life history framework and the adaptive calibration model, and consider how physiological stress response systems and related neuroendocrine processes may function as plasticity mechanisms. We then address the evolution of individual differences in susceptibility to the environment, which engenders systematic person–environment interactions in the effects of stress on development. Finally, we discuss stress-mediated regulation of pubertal development as a case study of how an evolutionary–developmental approach can foster theoretical integration.