Father absence and age at menarche : A test of four evolutionary models

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.

Associations of Father and Adult Male Presence with First Pregnancy and HIV Infection: Longitudinal Evidence from Adolescent Girls and Young Women in Rural South Africa (HPTN 068)

This study, a secondary analysis of the HPTN 068 randomized control trial, aimed to quantify the association of father and male presence with HIV incidence and first pregnancy among 2533 school-going adolescent girls and young women (AGYW) in rural South Africa participating in the trial between March 2011 and April 2017. Participants' ages ranged from 13-20 years at study enrollment and 17-25 at the post-intervention visit. HIV and pregnancy incidence rates were calculated for each level of the exposure variables using Poisson regression, adjusted for age using restricted quadratic spline variables, and, in the case of pregnancy, also adjusted for whether the household received a social grant. Our study found that AGYW whose fathers were deceased and adult males were absent from the household were most at risk for incidence of first pregnancy and HIV (pregnancy: aIRR = 1.30, Wald 95% CI 1.05, 1.61, Wald chi-square p = 0.016; HIV: aIRR = 1.27, Wald 95% CI 0.84, 1.91, Wald chi-square p = 0.263) as compared to AGYW whose biological fathers resided with them. For AGYW whose fathers were deceased, having other adult males present as household members seemed to attenuate the incidence (pregnancy: aIRR = 0.92, Wald 95% CI 0.74, 1.15, Wald chi-square p = 0.462; HIV: aIRR = 0.90, Wald 95% CI 0.58, 1.39, Wald chi-square p = 0.623) such that it was similar, and therefore not statistically significantly different, to AGYW whose fathers were present in the household.

Meta-Analysis of Direct and Indirect Effects of Father Absence on Menarcheal Timing

Despite extensive evidence of the association between father absence and early onset of menarche, whether father absence directly accelerates the onset of menarche or the association is mediated by other negative family psychosocial processes remains unclear. Reliable theories on the basis of which father absence has been investigated also vary. Within the life history (LH) theoretical framework, we conducted a meta-analysis of studies that investigated father absence, menarcheal timing, and various family disturbances that cause stress in children. We tested the hypothesis that father absence exerts a direct effect on menarcheal timing and an indirect effect on menarcheal timing mediated by integrated childhood stress. Quantitative synthesis using a two-stage meta-analytic structural equation modeling approach was applied to test our hypothesis. Based on seven research articles (N = 4,619) that include at least one form of family stressor as well as father absence and menarcheal timing, integrated childhood stress emerged as a robust mediator of the association between father absence and early menarcheal timing, and the total effect of father absence on menarcheal timing had reduced in size after accounting for the mediating effect of childhood stress. The findings emphasize the importance of a father figure in regulating a child's LH, including menarcheal timing.

Effects of Individual Mortality Experience on Out-of-Wedlock Fertility in Eighteenth- and Nineteenth-Century Krummhörn, Germany

Life history theory predicts that exposure to high mortality in early childhood leads to faster and riskier reproductive strategies. Individuals who grew up in a high mortality regime will not overly wait until they find a suitable partner and form a stable union because premature death would prevent them from reproducing. Cox proportional hazard models were used to determine whether women who experienced sibling death during early childhood (0–5 years) reproduced earlier and were at an increased risk of giving birth to an illegitimate child, with illegitimacy serving as a proxy for risky sexual behavior. Furthermore, we investigate whether giving birth out of wedlock is influenced by individual mortality experience or by more promiscuous sexual behavior that is clustered in certain families. Models are fitted on pedigree data from the eighteenth- and nineteenth-century Krummhörn population in Germany. The results show a relationship between sibling death in early childhood and the risk of reproducing out of wedlock, and reproductive timing. The risk of giving birth out of wedlock is linked to individual mortality experience rather than to family-level effects. In contrast, adjustments in connubial reproductive timing are influenced more by family-level effects than by individual mortality experience.

Hormones and human developmental plasticity

Natural selection favors the evolution of mechanisms that optimize the allocation of resources and time among competing traits. Hormones mediate developmental plasticity, the changes in the phenotype that occur during ontogeny. Despite their highly conserved functions, the flexibilities of human hormonal systems suggest a strong history of adaptation to variable environments. Physiological research on developmental plasticity has focused on the early programming effects of stress, the hypothalamus-pituitary-adrenal axis (HPAA) and the hypothalamus-pituitary-gonadal axis (HPGA) during critical periods, when the hormones produced have the strongest influence on the developing brain. Often this research emphasizes the maladaptive effects of early stressful experiences. Here we posit that the HPAA and HPAG systems in human developmental plasticity have evolved to be responsive to complex and dynamic problems associated with human sociality. The lengthy period of human offspring dependency, and its associated brain development and risks, is linked to the uniquely human combination of stable breeding bonds, extensive paternal effort in a multi-male group, extended bilateral kin recognition, grandparenting, and controlled exchange of mates among kin groups. We evaluate an evolutionary framework that integrates proximate physiological explanations with ontogeny, phylogeny, adaptive function, and comparative life history data.

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

Girls who experience father absence in childhood also experience accelerated reproductive development in comparison with peers with present fathers. One hypothesis advanced to explain this empirical pattern is genetic confounding, wherein gene-environment correlation (rGE) causes a spurious relationship between father absence and reproductive timing. We test this hypothesis by constructing polygenic scores for age at menarche and first birth using recently available genome-wide association study results and molecular genetic data on a sample of non-Hispanic white females from the National Longitudinal Study of Adolescent to Adult Health. We find that young women's accelerated menarche polygenic scores are unrelated to their exposure to father absence. In contrast, polygenic scores for earlier age at first birth tend to be higher in young women raised in homes with absent fathers. Nevertheless, father absence and the polygenic scores independently and additively predict reproductive timing. We find no evidence in support of the rGE hypothesis for accelerated menarche and only limited evidence in support of the rGE hypothesis for earlier age at first birth.

The Null Relation between Father Absence and Earlier Menarche

Researchers have claimed that the absence of a biological father accelerates the daughter's menarche. This claim was assessed by employing a large and nationally representative sample of Indonesian women. We analyzed 11,138 ever-married women aged 15+ in the Indonesian Family Life Survey 2015. We regressed age at menarche on the interaction of father absence (vs. presence) and mother absence (vs. presence) at age 12 with or without childhood covariates. For robustness checks, we performed a power analysis, re-ran the same specification for various subgroups, and varied the independent variable of interest. All results produced a null relation between father absence and age at menarche. The power analysis suggests that a false negative was unlikely. Our review of the literature indicates that the claim of the relation between father absence and earlier menarche was based on weak statistical foundations. Other studies with higher-quality datasets tended to find no relation, and our results replicated this tendency. Therefore, the influence of father absence does not appear to be universal.

Race disparities in pubertal timing: Implications for cardiovascular disease risk among African American women

Compared to white girls, sexual maturation is accelerated in African American girls as measured by indicators of pubertal development, including age at first menses. Increasing epidemiological evidence suggests that the timing of pubertal development may have strong implications for cardio-metabolic health in adolescence and adulthood. In fact, younger menarcheal age has been related prospectively to poorer cardiovascular risk factor profiles, a worsening of these profiles over time, and an increase in risk for cardiovascular events, including non-fatal incident cardiovascular disease and cardiovascular-specific and all-cause mortality. Yet, because this literature has been limited almost exclusively to white girls/women, whether this same association is present among African American girls/women has not been clarified. In the current narrative review, the well-established vulnerability of African American girls to experience earlier pubertal onset is discussed as are findings from literatures examining the health outcomes of earlier pubertal timing and its antecedents, including early life adversity exposures often experienced disproportionately in African American girls. Gaps in these literatures are highlighted especially with respect to the paucity of research among minority girls/women, and a conceptual framework is posited suggesting disparities in pubertal timing between African American and white girls may partially contribute to well-established disparities in adulthood risk for cardio-metabolic disease between African American and white women. Future research in these areas may point to novel areas for intervention in preventing or lessening the heightened cardio-metabolic risk among African American women, an important public health objective.

Adverse Childhood Environment: Relationship With Sexual Risk Behaviors and Marital Status in a Large American Sample

A substantial theoretical and empirical literature suggests that stressful events in childhood influence the timing and patterning of subsequent sexual and reproductive behaviors. Stressful childhood environments have been predicted to produce a life history strategy in which adults are oriented more toward short-term mating behaviors and less toward behaviors consistent with longevity. This article tests the hypothesis that adverse childhood environment will predict adult outcomes in two areas: risky sexual behavior (engagement in sexual risk behavior or having taken an HIV test) and marital status (currently married vs. never married, divorced, or a member of an unmarried couple). Data come from the Behavioral Risk Factor Surveillance System. The sample contains 17,530 men and 23,978 women aged 18-54 years living in 13 U.S. states plus the District of Columbia. Adverse childhood environment is assessed through 11 retrospective measures of childhood environment, including having grown up with someone who was depressed or mentally ill, who was an alcoholic, who used or abused drugs, or who served time in prison; whether one's parents divorced in childhood; and two scales measuring childhood exposure to violence and to sexual trauma. The results indicate that adverse childhood environment is associated with increased likelihood of engaging in sexual risk behaviors or taking an HIV test, and increased likelihood of being in an unmarried couple or divorced/separated, for both men and women. The predictions are supported by the data, lending further support to the hypothesis that childhood environments influence adult reproductive strategy.

Life history factors, personality and the social clustering of sexual experience in adolescents

Adolescent sexual behaviour may show clustering in neighbourhoods, schools and friendship networks. This study aims to assess how experience with sexual intercourse clusters across the social world of adolescents and whether predictors implicated by life history theory or personality traits can account for its between-individual variation and social patterning. Using data on 2877 adolescents from the Avon Longitudinal Study of Parents and Children, we ran logistic multiple classification models to assess the clustering of sexual experience by approximately 17.5 years in schools, neighbourhoods and friendship networks. We examined how much clustering at particular levels could be accounted for by life history predictors and Big Five personality factors. Sexual experience exhibited substantial clustering in friendship networks, while clustering at the level of schools and neighbourhoods was minimal, suggesting a limited role for socio-ecological influences at those levels. While life history predictors did account for some variation in sexual experience, they did not explain clustering in friendship networks. Personality, especially extraversion, explained about a quarter of friends' similarity. After accounting for life history factors and personality, substantial unexplained similarity among friends remained, which may reflect a tendency to associate with similar individuals or the social transmission of behavioural norms.

Early Menarche is Associated With Preference for Masculine Male Faces and Younger Preferred Age to Have a First Child

One developmental factor that is associated with variation in reproductive strategy is pubertal timing. For instance, women who experience earlier menarche have their first pregnancy earlier and prefer more masculinized male voices. Early menarche may also lead to preferences for masculine faces, but no study has shown such a link. We therefore investigated the relationships between pubertal timing, reproductive plans, sexual attitudes and behaviors, and masculinity preferences in nulliparous women aged 18–30 from the United Kingdom ( N = 10,793). We found that women who experienced earlier menarche reported a younger preferred age to have a first child and showed stronger masculinity preferences. This provides evidence that women experiencing early menarche not only have children earlier but notably plan to have children earlier. Additionally, our findings provide evidence that age of menarche influences partner selection, which is instrumental for the implementation of reproductive strategies.

Father absence and reproduction-related outcomes in Malaysia, a transitional fertility population

Father absence is consistently associated with children’s reproductive outcomes in industrialized countries. It has been suggested that father absence acts as a cue to particular environmental conditions that influence life history strategies. Much less is known, however, about the effects of father absence on such outcomes in lower-income countries. Using data from the 1988 Malaysian Family Life Survey (n = 567), we tested the effect of father absence on daughters’ age at menarche, first marriage, and first birth; parity progression rates; and desired completed family size in Malaysia, a country undergoing an economic and fertility transition. Father absence during later childhood (ages 8 to 15), although not during earlier childhood, was associated with earlier progressions to first marriage and first birth, after controlling for other confounders. Father absence does not affect age at menarche, desired family size, or progression from first to second birth. The patterns found in this transitional population partly mirror those in developed societies, where father absence accelerates reproductive events. There is, however, a notable contrast between the acceleration in menarche for father-absent girls consistently found in developed societies and the lack of any association in our findings. The mechanisms through which father absence affects reproduction may differ in different ecological contexts. In lower-income contexts, direct paternal investment or influence may be of more importance in determining reproductive behavior than whether fathers act as a cue to environmental conditions.

Adult bone strength of children from single-parent families: the Midlife in the United States Study

Bone health may be negatively impacted by childhood socio-environmental circumstances. We examined the independent associations of single-parent childhood and parental death or divorce in childhood with adult bone strength indices. Longer exposure to a single-parent household in childhood was associated with lower bone strength in adulthood.

INTRODUCTION

Because peak bone mass is acquired during childhood, bone health may be negatively impacted by childhood socio-environmental disadvantage. The goal of this study was to determine whether being raised in a single-parent household is associated with lower bone strength in adulthood.

METHODS

Using dual-energy X-ray absorptiometry data from 708 participants (mean age 57 years) in the Midlife in the United States Biomarker Project, we examined the independent associations of composite indices of femoral neck bone strength relative to load (in three failure modes: compression, bending, and impact) in adulthood with the experience of single-parent childhood and parental death or divorce in childhood.

RESULTS

After adjustment for gender, race, menopause transition stage, age, and body mass index, each additional year of single-parent childhood was associated with 0.02 to 0.03 SD lower indices of adult femoral neck strength. In those with 9-16 years of single-parent childhood, the compression strength index was 0.41 SD lower, bending strength index was 0.31 SD lower, and impact strength index was 0.25 SD lower (all p values < 0.05). In contrast, parental death or divorce during childhood was not by itself independently associated with adult bone strength indices. The magnitudes of these associations were unaltered by additional adjustment for lifestyle factors and socioeconomic status in childhood and adulthood.

CONCLUSIONS

Independent of parental death or divorce, growing up in a single-parent household is associated with lower femoral neck bone strength in adulthood, and this association is not entirely explained by childhood or adult socioeconomic conditions or lifestyle choices.

Nonresident fatherhood and adolescent sexual behavior: a comparison of siblings approach

Although voluminous research has linked nonresident fatherhood to riskier sexual behavior in adolescence, including earlier sexual debut, neither the causality of that link nor the mechanism accounting for it has been well-established. Using data from the National Longitudinal Survey of Youth, 1979-the Young Adult Survey (CNLSY-YA), the present study addresses both questions by comparing the sexual development of siblings discordant for age at father departure from the home and examining results across behavioral (age at first intercourse), biological (pubertal timing), and cognitive (attitudes about childbearing and marriage) sexual outcomes (N = 5,542). Findings indicate that nonresident fatherhood, beginning either at birth or during middle childhood, leads to an earlier sexual debut for girls, but not for boys, an effect likely explained by weak parental monitoring rather than an accelerated reproductive strategy.

Behavior problems and timing of menarche: a developmental longitudinal biometrical analysis using the NLSY-Children data

A powerful longitudinal data source, the National Longitudinal Survey of Youth Children data, allows measurement of behavior problems (BP) within a developmental perspective linking them to menarcheal timing (MT). In a preliminary analysis, we evaluate the bivariate relationships between BP measured at different developmental periods and the timing of menarche. Correlations were not consistent with any correlational/causal relationship between BP and MT. In the major part of our study, MT was used to moderate the developmental trajectory of BP, within a genetically-informed design. Girls reaching menarche early had behavior problem variance accounted for by the shared environment; those reaching menarche with average/late timing had behavior problem differences accounted for by genetic variance. Our findings match previous empirical results in important ways, and also extend those results. A theoretical interpretation is offered in relation to a theory linking genetic/shared environmental variance to flexibility and choices available within the family in relation to BP.

Intergenerational conflicts may help explain parental absence effects on reproductive timing: a model of age at first birth in humans

Background. Parental absences in childhood are often associated with accelerated reproductive maturity in humans. These results are counterintuitive for evolutionary social scientists because reductions in parental investment should be detrimental for offspring, but earlier reproduction is generally associated with higher fitness. In this paper we discuss a neglected hypothesis that early reproduction is often associated with parental absence because it decreases the average relatedness of a developing child to her future siblings. Family members often help each other reproduce, meaning that parents and offspring may find themselves in competition over reproductive opportunities. In these intergenerational negotiations offspring will have less incentive to help the remaining parent rear future half-siblings relative to beginning reproduction themselves.

Method. We illustrate this “intergenerational conflict hypothesis” with a formal game-theoretic model.

Results. We show that when resources constrain reproductive opportunities within the family, parents will generally win reproductive conflicts with their offspring, i.e., they will produce more children of their own and therefore delay existing offsprings’ reproduction. This is due to the asymmetric relatedness between grandparents and grandchildren (r = .25), compared to siblings (r = 0.5), resulting in greater incentives for older siblings to help rear younger siblings than for grandparents to help rear grandchildren. However, if a parent loses or replaces their partner, the conflict between the parent and offspring becomes symmetric since half siblings are as related to one another as grandparents are to grandchildren. This means that the offspring stand to gain more from earlier reproduction when their remaining parent would produce half, rather than full, siblings. We further show that if parents senesce in a way that decreases the quality of their infant relative to their offspring’s infant, the intergenerational conflict can shift to favor the younger generation.

FREQUENT RESIDENTIAL RELOCATIONS CUMULATIVELY ACCELERATE MENARCHEAL TIMING IN A SAMPLE OF ENGLISH ADOLESCENT GIRLS

Childhood adversity has been associated with accelerated menarcheal and reproductive timing in females. The relationship between family- and neighbourhood-level measures of childhood adversity, menarcheal timing and intended reproductive timing was investigated in a sample of 354 English adolescent girls. The data were collected from March to June 2012. In total 90 of the participants had reached menarche. Frequent residential relocations increased the likelihood of reaching menarche (HR 1.11; 95%CI 1.02-1.22). Girls who had moved house one to four times or five or more times, were respectively, more than twice (HR 2.14; 95%CI 1.23-3.73) and more than three times (HR 3.20; 95%CI 1.44-7.10) as likely to have reached menarche than girls who had never moved house. Frequent residential relocations were associated with stepfather co-residence, increased number of half/stepsiblings and reduced feelings of family support. Menarche was also accelerated by the presence of half/stepsisters. There was no relationship between menarcheal timing and intended reproductive timing. Frequent residential relocations may indicate instability in a young person's life, which is often outside of their control. Extending childhood adversity measures to include residential relocations could be important in better understanding the role early life events play in accelerating menarche.

A Life History Theory of Father Absence and Menarche: A Meta-Analysis

Is the absence of biological fathers related to their daughters' earlier age at menarche? Drawing on evolutionary psychology and life history theory, prior research has suggested such a relationship ( Belsky, Steinberg, and Draper, 1991 ; Draper and Harpending, 1982 ; Ellis, 2004 ). Although qualitative reviews have shown narrative support for this relationship ( Allison and Hyde, 2013 ; Ellis, 2004 ; Kim, Smith, and Palermiti, 1997 ; Susman and Dorn, 2009 ), no quantitative review exists to provide empirical support for this relationship or to explain mixed results. Thus, we conducted a random-effects meta-analysis of correlations ( Card, 2012 ) on father absence and daughter menarcheal age ( k = 33; N = 70,403). The weighted mean correlation was .14, 95% CI [.09, .19], suggesting that father absence was significantly related to earlier menarche; effect sizes were heterogeneous. Egger's regression ( Egger, Smith, Schneider, and Minder, 1997 ) showed no evidence of publication bias (file-drawer effect; r = .34, p = .052). Outcome measure differences (menarcheal age vs. menarcheal age embedded in a multi-item pubertal timing scale) did not moderate effect sizes. Study year effects ( Schooler, 2011 ) were also non-significant. Our findings support one aspect of the life history model and provide groundwork for subsequent examination of other pathways in the model.

Father absence and age at first birth in a Western sample

OBJECTIVES

Although a large literature has shown links between "father absence" during early childhood, and earlier puberty and sexual behavior in girls in Western populations, there are only a few studies which have looked at timing of reproduction, and only one of these fully incorporated childless respondents to investigate whether father absence is associated with increased hazard of becoming a parent at one time point (early) more than another. Here we sought to clarify exactly when, if at all, father absence increased the likelihood of first birth in a Western sample.

METHODS

An online sample of 954 women reported on their childhood living circumstances, their age of menarche, first coitus, first pregnancy, and first birth.

RESULTS

Cox regression and Kaplan-Meier plots showed an increased risk of becoming a parent for father absent women in their 20s, but no overall greater likelihood of parenthood.

CONCLUSION

These data support the suggestion that father absence is associated with an acceleration of reproductive behavior in Western samples, rather than a simple increase in likelihood of reproduction.

Family relationships in childhood, pubertal timing, and subsequent reproductive strategies among adolescents

The evolutionary theory of socialization of Belsky, Steinberg, and Draper was investigated on the empirical basis of a longitudinal sample of 26 adolescent girls and boys who were born in Berlin during German reunification, as well as their mothers. Consistent with the theory, pubertal timing of the girls (but not of the boys) was predicted by the quality of parental relations in childhood, and pubertal timing of the girls (but not of the boys) was a significant predictor of the age at first intercourse. The results suggest that there are different developmental pathways for girls and boys with respect to the predictions of the evolutionary theory of socialization of Belsky et al. The findings also support the hypothesis that early onset of reproduction and frequent reproduction may be two different aspects of a quantitative reproductive strategy.

Life-course origins of the ages at menarche and menopause

A woman's age at menarche (first menstrual period) and her age at menopause are the alpha and omega of her reproductive years. The timing of these milestones is critical for a woman's health trajectory over her lifespan, as they are indicators of ovarian function and aging. Both early and late timing of either event are associated with risk for adverse health and psychosocial outcomes. Thus, the search for a relationship between age at menarche and menopause has consequences for chronic disease prevention and implications for public health. This article is a review of evidence from the fields of developmental biology, epidemiology, nutrition, demography, sociology, and psychology that examine the menarche-menopause connection. Trends in ages at menarche and menopause worldwide and in subpopulations are presented; however, challenges exist in constructing trends. Among 36 studies that examine the association between the two sentinel events, ten reported a significant direct association, two an inverse association, and the remainder had null findings. Multiple factors, including hormonal and environmental exposures, socioeconomic status, and stress throughout the life course are hypothesized to influence the tempo of growth, including body size and height, development, menarche, menopause, and the aging process in women. The complexity of these factors and the pathways related to their effects on each sentinel event complicate evaluation of the relationship between menarche and menopause. Limitations of past investigations are discussed, including lack of comparability of socioeconomic status indicators and biomarker use across studies, while minority group differences have received scant attention. Suggestions for future directions are proposed. As research across endocrinology, epidemiology, and the social sciences becomes more integrated, the confluence of perspectives will yield a richer understanding of the influences on the tempo of a woman's reproductive life cycle as well as accelerate progress toward more sophisticated preventive strategies for chronic disease.

Early Menarche as an Alternative Reproductive Tactic in Human Females: An Evolutionary Approach to Reproductive Health Issues

The age at which a female reaches sexual maturity is critical in determining her future reproductive health and success. Thus, a worldwide decline in menarcheal age (timing of first menstrual period) may have serious long-term consequences. Early menarcheal timing (first menstrual period before age 12) can have a negative effect on fecundity, as well as the quality and quantity of offspring, and may consequently influence population growth or decline. In this paper, we apply an evolutionary framework to modern human health, and assess both proximate and ultimate consequences of declining menarcheal age. Examination of human reproductive health within an evolutionary framework is innovative and essential, because it illuminates the ultimate consequences of a declining age of menarche and facilitates new ways of thinking about the long-term and intergenerational transmission of health and disease; thus, an evolutionary framework lends itself to innovative public health and policy programs. In this paper, we examine whether or not early menarche is an alternative reproductive tactic that modern human females employ in response to a stressful environment, and whether or not early menarche is ultimately beneficial.

Flexibility in reproductive timing in human females: integrating ultimate and proximate explanations

From an ultimate perspective, the age of onset of female reproduction should be sensitive to variation in mortality rates, and variation in the productivity of non-reproductive activities. In accordance with this prediction, most of the cross-national variation in women's age at first birth can be explained by differences in female life expectancies and incomes. The within-country variation in England shows a similar pattern: women have children younger in neighbourhoods where the expectation of healthy life is shorter and incomes are lower. I consider the proximate mechanisms likely to be involved in producing locally appropriate reproductive decisions. There is evidence suggesting that developmental induction, social learning and contextual evocation may all play a role.

Reported early family environment covaries with menarcheal age as a function of polymorphic variation in estrogen receptor-α

Age at menarche, a sentinel index of pubertal maturation, was examined in relation to early family relationships (conflict, cohesion) and polymorphic variation in the gene encoding estrogen receptor-α (ESR1) in a midlife sample of 455 European American women. Consistent with prior literature, women who reported being raised in families characterized by close interpersonal relationships and little conflict tended to reach menarche at a later age than participants reared in families lacking cohesion and prone to discord. Moreover, this association was moderated by ESR1 variation, such that quality of the family environment covaried positively with menarcheal age among participants homozygous for minor alleles of the two ESR1 polymorphisms studied here (rs9304799, rs2234693), but not among women of other ESR1 genotypes. In addition, (a) family relationship variables were unrelated to ESR1 variation, and (b) genotype-dependent effects of childhood environment on age at menarche could not be accounted for by personality traits elsewhere shown to explain heritable variation in reported family conflict and cohesion. These findings are consistent with theories of differential susceptibility to environmental influence, as well as the more specific hypothesis (by Belsky) that girls differ genetically in their sensitivity to rearing effects on pubertal maturation.

The Effect of Life Expectancy on Aggression and Generativity: A Life History Perspective

Following a model that is inclusive of both dispositional and situational influences on life-history behaviors and attitudes, the effect of life expectancies on aggression and generativity was examined. Consistent with the hypotheses it was found that shorter life expectancies led to an increase in the desire to aggress and a decrease in the desire to engage in generative behaviors. The results are discussed in terms of how life history theory can be used to frame research on person-situation interactions.

Investimento materno e história reprodutiva de mães residentes em contextos com diferentes graus de urbanização

A presente pesquisa tem como objetivo caracterizar o investimento materno e a história reprodutiva de mães que vivem em diferentes contextos. Para tal, 150 mães que residiam em três contextos com diferentes graus de urbanização foram entrevistadas. Por meio da análise estatística dos dados constatou-se que houve diferenças significativas entre os contextos, além de correlações positivas entre os núcleos reprodutivos, como idade da primeira relação sexual e idade da mãe no nascimento do primeiro filho. Conclui-se que as estratégias reprodutivas são influenciadas pela história de vida das mães, das condições sociodemográficas atuais e do contexto onde vivem.

Eriksonian Lifespan Theory and Life History Theory: An Integration Using the Example of Identity Formation

Furthering the cause of consilience in the social sciences a model is proposed in which Eriksonian life span theory and life history theory are integrated. The model explains individual differences in the Eriksonian developmental stages as a function of the individual differences in developmental trajectories of life history theory as conceptualized by Belsky, Steinberg, and Draper (1991) . Erikson's fifth stage of identity formation is used to examine the model, with the results of three studies presented to illustrate the viability of the model. Future research should examine other aspects of the model and the relationship between the developmental trajectories in life history theory and the Eriksonian stages in greater detail.

Adaptive developmental plasticity might not contribute much to the adaptiveness of reproductive strategies

Del Giudice's model belongs among those that highlight the role of adaptive developmental plasticity in human reproductive strategies; but at least three other forms of evolutionary adaptation also influence reproductive behavior. Similar to earlier models, the existing evidence suggests that Del Giudice's hypothesized effects are rather weak. In particular, adult attachment styles are hardly predictive of outcomes visible to natural selection.

Attachment strategies across sex, ontogeny, and relationship type

We propose that middle childhood female ambivalent attachment, given the adaptive problem of uncertainty of future investment, is designed to evoke immediate investment from current caregivers, rather than new investment sources. We suggest greater specificity of strategic attachment solutions to adaptive problems that differ by sex, time, and relationship type.

Family rearing antecedents of pubertal timing

Two general evolutionary hypotheses were tested on 756 White children (397 girls) studied longitudinally: (1) rearing experiences would predict pubertal timing; and (2) children would prove differentially susceptible to rearing. Analysis of pubertal measurements, including some based on repeated physical assessments, showed that mothering and fathering, earlier and later in childhood, predicted pubertal development, but only for girls, with negative parenting appearing most influential; maternal harsh control predicted earlier menarche. Rearing effects varied by infant negative emotionality, proving stronger (and opposite) for girls who in infancy were lower rather than higher in negativity. Maternal menarche, controlled in all analyses, was a stronger predictor than rearing. Findings are discussed in terms of theory development, genetic and nutritional influences, and sample restrictions.

Reproductive strategy, sexual development and attraction to facial characteristics

Sexual reproduction strategies vary both between and within species in the level of investment in offspring. Life-history theories suggest that the rate of sexual maturation is critically linked to reproductive strategy, with high investment being associated with few offspring and delayed maturation. For humans, age of puberty and age of first sex are two developmental milestones that have been associated with reproductive strategies. Stress during early development can retard or accelerate sexual maturation and reproduction. Early age of menarche is associated with absence of younger siblings, absence of a father figure during early life and increased weight. Father absence during early life is also associated with early marriage, pregnancy and divorce. Choice of partner characteristics is critical to successful implementation of sexual strategies. It has been suggested that sexually dimorphic traits (including those evident in the face) signal high-quality immune function and reproductive status. Masculinity in males has also been associated with low investment in mate and offspring. Thus, women's reproductive strategy should be matched to the probability of male investment, hence to male masculinity. Our review leads us to predict associations between the rate of sexual maturation and adult preferences for facial characteristics (enhanced sexual dimorphism and attractiveness). We find for men, engaging in sex at an early age is related to an increased preference for feminized female faces. Similarly, for women, the earlier the age of first sex the greater the preference for masculinity in opposite-sex faces. When we controlled sexual dimorphism in male faces, the speed of sexual development in women was not associated with differences in preference for male facial attractiveness. These developmental influences on partner choice were not mediated by self-rated attractiveness or parental relationships. We conclude that individuals assort in preferences based on the rapidity of their sexual development. Fast developing individuals prefer opposite-sex partners with an increased level of sexually dimorphic facial characteristics.

A life history assessment of early childhood sexual abuse in women

Life history theory provided a framework for examining the relations among child sexual abuse (CSA), childhood adversity, and patterns of reproductive development and behavior. A community survey that assessed CSA, life history variables (e.g., age of menarche), and social and family background was administered to 623 women (mean age=26.9 years). Independent of social and family background, CSA was associated with earlier age of (a) menarche, (b) first sexual relationship, (c) desire to have children, (d) first childbirth, and (e) lower self-evaluated physical attractiveness. Cluster analyses revealed different patterns of experiential correlates of reproductive development within the group of abused women, suggesting CSA may operate in combination with other childhood circumstances to modify the timing and pattern of individual maturation.

Timing of pubertal maturation in girls: an integrated life history approach

Life history theory provides a metatheoretical framework for the study of pubertal timing from an evolutionary-developmental perspective. The current article reviews 5 middle-level theories--energetics theory, stress-suppression theory, psychosocial acceleration theory, paternal investment theory, and child development theory--each of which applies the basic assumptions of life history theory to the question of environmental influences on timing of puberty in girls. These theories converge in their conceptualization of pubertal timing as responsive to ecological conditions but diverge in their conceptualization of (a) the nature, extent, and direction of environmental influences and (b) the effects of pubertal timing on other reproductive variables. Competing hypotheses derived from the 5 perspectives are evaluated. An extension of W. T. Boyce and B. J. Ellis's (in press) theory of stress reactivity is proposed to account for both inhibiting and accelerating effects of psychosocial stress on timing of pubertal development. This review highlights the multiplicity of (often unrecognized) perspectives guiding research, raises challenges to virtually all of these, and presents an alternative framework in an effort to move research forward in this arena of multidisciplinary inquiry.