Family relations in early childhood and reproductive development

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.

Opportunity and the sexual abuse of adolescents

OBJECTIVES

The risk of sexual abuse victimization was examined from a routine activity perspective. For comparison, predictors of sexual encounters with same-age peers were also examined.

METHODS

Analyses were based on a nationally representative sample of 24,823 Finnish youth who responded to questions about their sexual encounters with peers and with someone outside their family who was at least five years older.

RESULTS

Adolescents who had older friends and parents who did not monitor their social relationships were at greater risk of sexual abuse and peer encounters. In addition, delinquent youth had a higher risk of abuse than non-delinquents, controlling for exposure. Delinquent youth were also more likely to have favorable attitudes toward the abuse, to initiate the sexual encounter, and to experience repeat victimizations. Physical attractiveness, but not sexual maturity, was related to abuse.

CONCLUSIONS

Risk of sexual abuse is positively related to exposure to older people, susceptibility to deviant influence, and the target's value to the offender. A full understanding of risk factors requires a consideration of the victims' characteristics and their compliant behavior.

Does puberty affect the development of behavior problems as a mediator, moderator, or unique predictor?

Pubertal timing matters for psychological development. Early maturation in girls is linked to risk for depression and externalizing problems in adolescence and possibly adulthood, and early and late maturation in boys are linked to depression. It is unclear whether pubertal timing uniquely predicts problems; it might instead mediate the continuity of behavior problems from childhood to adolescence or create psychological risk specifically in youth with existing problems, thus moderating the link. We investigated these issues in 534 girls and 550 boys, measuring pubertal timing by a logistic model fit to annual self-report measures of development and, in girls, age at menarche. Prepuberty internalizing and externalizing behavior problems were reported by parents. Adolescent behavior problems were reported by parents and youth. As expected, behavior problems were moderately stable. Pubertal timing was not predicted by childhood problems, so it did not mediate the continuity of behavior problems from childhood to adolescence. Pubertal timing did not moderate links between early and later problems for girls. For boys, early maturation accentuated the link between childhood problems and adolescent substance use. Overall, the replicated links between puberty and behavior problems appear to reflect the unique effects of puberty and child behavior problems on the development of adolescent behavior problems.

Transitions in body and behavior: a meta-analytic study on the relationship between pubertal development and adolescent sexual behavior

The present meta-analysis studies the relations of pubertal timing and status with sexual behavior and sexual risk behavior among youth aged 10.5-22.4 years. We included biological sex, age, and ethnicity as potential moderators. Four databases were searched for studies (published between 1980 and 2012) on the relation between pubertal timing or status and sexual behavior. The outcomes were (1) sexual intercourse; (2) combined sexual behavior; and (3) risky sexual behavior. Earlier pubertal timing or more advanced pubertal status was related to earlier and more sexual behavior, and earlier pubertal timing was related to more risky sexual behavior. Further, the links between (1) pubertal status and combined sexual behavior and (2) pubertal timing and sexual intercourse status, combined sexual behavior, and risky sexual behavior were stronger for girls than boys. Most links between pubertal status, timing, and sexual behavior and sexual risk behavior were stronger for younger adolescents. Moderation by ethnicity did not yield consistent results. There was significant variation in results among studies that was not fully explained by differences in biological sex, age, and ethnicity. Future research is needed to identify moderators that explain the variation in effects and to design sexual health interventions for young adolescents.

Individual change and the timing and onset of important life events

Researchers are often interested in studying how the timing of a specific event affects concurrent and future development. When faced with such research questions there are multiple statistical models to consider and those models are the focus of this paper as well as their theoretical underpinnings and assumptions regarding the nature of the effect of the event on the developmental process. We discuss three models, all variants of growth models specified within the multilevel modeling framework, which conceptualize the developmental process and the effect of the event in different ways. These models include the growth model with a time-invariant covariate, the growth model with a time-varying covariate, and the spline growth model. After discussing the models in detail, we applied these models to longitudinal data from the Berkeley Growth Study to examine cognitive changes during infancy and the effect of independent sitting on those changes. Results suggest that research conclusions depend on the model chosen and how certain results can be misconstrued unless the model accurately reflects the research questions. Recommendations and additional non-traditional models are discussed.

A not-so-grim tale: how childhood family structure influences reproductive and risk-taking outcomes in a historical U.S. Population

Childhood family structure has been shown to play an important role in shaping a child's life course development, especially in industrialised societies. One hypothesis which could explain such findings is that parental investment is likely to be diluted in families without both natural parents. Most empirical studies have examined the influence of only one type of family disruption or composition (e.g. father absence) making it difficult to simultaneously compare the effects of different kinds of family structure on children's future outcomes. Here we use a large, rich data source (n = 16,207) collected by Alfred Kinsey and colleagues in the United States from 1938 to 1963, to examine the effects of particular childhood family compositions and compare between them. The dataset further allows us to look at the effects of family structure on an array of traits relating to sexual maturity, reproduction, and risk-taking. Our results show that, for both sexes, living with a single mother or mother and stepfather during childhood was often associated with faster progression to life history events and greater propensity for risk-taking behaviours. However, living with a single father or father and stepmother was typically not significantly different to having both natural parents for these outcomes. Our results withstand adjustment for socioeconomic status, age, ethnicity, age at puberty (where applicable), and sibling configuration. While these results support the hypothesis that early family environment influences subsequent reproductive strategy, the different responses to the presence or absence of different parental figures in the household rearing environment suggests that particular family constructions exert independent influences on childhood outcomes. Our results suggest that father-absent households (i.e. single mothers or mothers and stepfathers) are most highly associated with subsequent fast life history progressions, compared with mother-absent households, and those with two natural parents.

Psychobehavioral Effects of Hormonal Contraceptive Use

Although female use of hormonal contraceptives (HCs) has been associated with a variety of physical side effects, the psychological and behavioral side effects have received comparatively little attention until recently. Indeed, the long-term impact of HC use on human psychology has been vastly under-researched and has only recently become a focus for mainstream scholars. Women who use HCs report higher rates of depression, reduced sexual functioning, and higher interest in short-term sexual relationships compared to their naturally-cycling counterparts. Also, HC use may alter women's ability to attract a mate, as well as the mate retention behaviors in both users and their romantic partners. Some evidence even suggests that HC use alters mate choice and may negatively affect sexual satisfaction in parous women, with potential effects on future offspring. Interestingly, HCs have become a standard method of population control for captive nonhuman primates, opening up exciting avenues for potential comparative research. Here, the existing literature on the psychobehavioral effects of HCs in humans and nonhuman primates is reviewed and discussed. The potential resulting downstream consequences for the path of human evolution and recommendations for how future research could tease apart the underlying causes of these psychobehavioral effects of HC use are discussed, including suggestions for research involving nonhuman primates.

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.

Adolescent sexual activity and the development of delinquent behavior: the role of relationship context

Despite the well-established association between adolescent sexual activity and delinquent behavior, little research has examined the potential importance of relationship contexts in moderating this association. The current study used longitudinal, behavioral genetic data on 519 same-sex twin pairs (48.6% female) divided into two age cohorts (13-15 and 16-18 years olds) drawn from the National Longitudinal Study of Adolescent Health. Analyses tested whether adolescent sexual activity that occurred in romantic versus non-romantic relationships was associated with delinquency from adolescence to early adulthood, after controlling for genetic influences. Results indicated that, for both younger and older adolescents, common underlying genes influence both sexual behavior and delinquency. After controlling for these genetic influences, there was no within-twin pair association between sexual activity and delinquency in younger adolescents. In older adolescents, sexual activity that occurred in romantic relationships predicted lower levels of delinquency, both cross-sectionally and longitudinally, whereas sexual activity in non-romantic relationships predicted higher levels of delinquency. These results are consistent with emerging research that suggests that the psychological correlates of adolescent sexual activity may be moderated by the social context in which this activity occurs.

Growing up under generalized violence: an ecological study of homicide rates and secular trends in age at menarche in Colombia, 1940s-1980s

We examined secular changes in mean age at menarche among 5577 Colombian women born between 1941 and 1989, and correlated those changes with nation-wide rates of homicide and real gross domestic product per capita (GDP) at the year of birth and at the year at age 5, within predefined historical periods. The mean (standard error) rate of change in age at menarche by year of birth was -0.55 (0.02) years/decade. The rate of change was not constant, but varied between historical periods as follows: -1.44, -0.14, -0.60, and -0.36 years/decade for the periods 1941-1947, 1948-1958, 1959-1978, and 1979-1989, respectively. The changes in age at menarche correlated positively with the changes in the nation-wide rates of homicide within such periods; i.e. decelerations in the menarcheal trend coincided with increases in the rates of homicide and vice versa. The correlation was higher with the rates of homicide when women were 5 years of age (r=0.99, p=0.01) compared to the rates of homicide at the year of birth (0.55, p=0.45). There were negative correlations between the changes in age at menarche and the changes in GDP, but they were weaker than those with the rates of homicide. These results could suggest a potential impact on maturation of psychosocial stress in childhood due to exposure to a generalized atmosphere of violence and fear.

Childhood abuse and early menarche: findings from the black women's health study

OBJECTIVES

We examined the association between childhood abuse and early menarche in a sample of US Black women.

METHODS

We conducted multivariable log-binomial regression on data from 35 330 participants in the Black Women's Health Study to estimate risk ratios and 95% confidence intervals for the relation of childhood physical and sexual abuse with early age at menarche (i.e., < 12 years).

RESULTS

In adjusted analyses, sexual abuse was positively associated with early menarche, and the risk of early menarche increased with increasing frequency of sexual abuse incidents. We observed a weak but statistically significant association between physical abuse and early menarche. Associations between sexual abuse and early menarche were stronger when we used a more stringent cutpoint for early menarche (i.e., < 11 years).

CONCLUSIONS

Our data suggest an increased risk of early menarche among Black women who experienced childhood sexual abuse. Evidence for an association between childhood physical abuse and early menarche was equivocal.

A critical review of the empirical literature on the relation between anxiety and puberty

The current paper critically reviews the empirical literature focused on the association between puberty and anxiety. A detailed review of more than 45 empirical articles is provided. There is some evidence that among girls, but not boys, a more advanced pubertal status (controlling for age) is associated with higher reported anxiety symptoms. Also among girls, earlier pubertal timing is linked to higher anxiety scores. It is unclear whether early puberty may lead to increased anxiety or if high anxiety influences pubertal timing. With respect to hormones, there were relatively few significant associations for girls, although this literature is very small. Among boys, several studies reported positive associations between both gonadal and adrenal hormones and anxiety. The direction of effect for these finding is also unstudied. The primary limitation of the hormone-anxiety literature pertains to the absence of pubertal measures in samples of youth in which hormones are measured. The paper concludes with a comprehensive examination of the methodological strengths and weaknesses of the literature and recommendations for future work.

Developmental plasticity of human reproductive development: effects of early family environment in modern-day France

In a first study, we investigated how the absence of a father and the presence of a stepfather during early childhood affected physiological and behavioral traits related to reproductive development (such as age of menarche, age of first sexual intercourse and number of sexual partners) in a large sample set of male and female French university students. We evaluated which ages were sensitive to modifications in the family composition and found that menarche occurred earlier when the father was absent, particularly when the child was between 0 and 5 years of age. Father absence during early adolescence was associated with a younger age at first sexual intercourse and an increased number of sexual partners, for both sexes. The presence of a stepfather during this period further advanced the age of first sexual intercourse. We also measured testosterone levels in both sexes and analyzed their association with parental separation, and found that young women with separated parents had significantly higher afternoon levels of testosterone. In a second study, we analyzed direct fitness measures (such as number of children and grandchildren) in a large sample of French workers and found that parental separation during childhood was not associated with fitness variation. We discuss whether the reproductive outcomes of individuals having experienced modifications in the early family environment are the expression of costs or adaptive strategies.

Biological, familial, and peer influences on dating in early adolescence

The current study examined the joint contributions of pubertal maturation, parental monitoring, involvement in older peer groups, peer dating, and peer delinquency on dating in a sample of early adolescent boys and girls. The sample consisted of 784 adolescents (394 boys, 390 girls) enrolled in grades 5, 6, and 7 who were followed for one year. In addition to measures of pubertal maturation and parental monitoring, adolescents and their peer group members completed indices of dating and delinquency. Average dating and delinquency scores for each participant's peer group network were computed. Results indicated that it was the combination of pubertal maturation, peer delinquency, and peer dating that explained increases in early dating. For boys only, parental monitoring was a significant predictor. The more knowledgeable parents were about their boys' activities, the lower the number of dating activities reported. These results highlight the importance of considering the joint effects of these biological and social predictors in understanding early dating. When rapid changes occur in all three domains, early dating is most likely to ensue. The findings of this study have practical importance. Parents and professionals who work closely with youth should attend to the special vulnerability of early maturing adolescents in the face of peer pressure and to the important role of parental monitoring in regulating dating activities.

Early puberty and adolescent pregnancy: the influence of alcohol use

OBJECTIVE

Early pubertal timing predicts deleterious outcomes for young girls, including substance use, risky sexual behavior, and pregnancy. In turn, adolescent pregnancy predicts long-term negative consequences such as reduced educational attainment and income-earning potential. Despite evidence of the direct links between early puberty and negative outcomes, this study is the first to examine the role that alcohol plays in the timing of sexual intercourse and pregnancy among early-maturing females.

DESIGN

Participants were 666 females, aged 18 to 22 years, from 4 major ethnic groups in Arizona (non-Hispanic white, black, Latino, and Native American). All women included in the sample had experienced a pregnancy in their teens or early 20s. Participants completed a self-administered questionnaire that inquired about their timing of menarche, sexual initiation, first alcohol use, and age at first pregnancy. A mediating model predicting age at pregnancy was tested by using path modeling.

RESULTS

Early puberty was found to be associated with earlier age of alcohol use and sexual initiation, which in turn predicted early pregnancy. Age at first sexual intercourse and age at first substance use significantly mediated the relation between age at menarche and age at first pregnancy. The results did not vary by ethnic group.

CONCLUSIONS

Girls who mature early are more likely to engage in early substance use and sexual intercourse, which in turn puts them at greater risk for adolescent pregnancy. It is important that health care providers are sensitive to the risks associated with early maturation among young girls and provide preventive screening, education, and counseling related to alcohol use and sexual initiation for this group.

Evolutionary perspectives on pregnancy: maternal age at menarche and infant birth weight

We present a novel evolutionary analysis of low birth weight (LBW). LBW is a well-known risk factor for increased infant morbidity and mortality. Its causes, however, remain obscure and there is a vital need for new approaches. Life history theory, the most dynamic branch of evolutionary ecology, provides important insights into the potential role of LBW in human reproductive strategies. Life history theory's primary rationale for LBW is the trade-off between current and future reproduction. This trade-off underlies the prediction that under conditions of environmental risk and uncertainty (experienced subjectively as psychosocial stress) it can be evolutionarily adaptive to reproduce at a young age. One component of early reproduction is early menarche. Early reproduction tends to maximise offspring quantity, but parental investment theory's assumption of a quantity-quality trade-off holds that maximizing offspring quantity reduces quality, of which LBW may be the major component. We therefore predict that women who experienced early psychosocial stress and had early menarche are more likely to produce LBW babies. Furthermore, the extension of parent-offspring conflict theory in utero suggests that the fetus will attempt to resist its mother's efforts to reduce its resources, allocating more of what it does receive to the placenta in order to extract more maternal resources to increase its own quality. We propose that LBW babies born to mothers who experience early psychosocial stress and have early menarche are more likely to have a higher placental/fetal weight ratio. We review evidence in support of these hypotheses and discuss the implications for public health.