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1.
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.  相似文献   

2.
This study examines female reproductive development from an evolutionary life history perspective. Retrospective data are for 10,847 U.S. women. Results indicate that timing of parental separation is associated with reproductive development and is not confounded with socioeconomic variables or phenotypic correlations with mothers' reproductive behavior. Divorce/separation between birth and 5 years predicted early menarche, first sexual intercourse, first pregnancy, and shorter duration of first marriage. Separation in adolescence was the strongest predictor of number of sex partners. Multiple changes in childhood caretaking environment were associated with early menarche, first sex, first pregnancy, greater number of sex partners, and shorter duration of marriage. Living with either the father or mother after separation had similar effect on reproductive development. Living with a stepfather showed a weak, but significant, association with reproductive development, however, duration of stepfather exposure was not a significant predictor of development. Difference in amount and quality of direct parental care (vs. indirect parental investment) in two- and single-parent households may be the primary factor linking family environment to reproductive development.  相似文献   

3.
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.  相似文献   

4.
Understanding the determinants of pubertal timing, particularly menarche in girls, is an important area of investigation owing to the many health, psychosocial, and demographic outcomes related to reproductive maturation. Traditional explanations emphasized the role of favorable nutrition in maturational acceleration. More recently, work has documented early maturity in relation to markers of familial and environmental instability (e.g. paternal absence), which are hypothesized to serve as cues triggering adaptive adjustment of life history scheduling. While these studies hint at an ability of human females to accelerate maturity in stressful environments, most have focused on populations characterized by energetic excess. The present study investigates the role of developmental nutrition alongside cues of environmental risk and instability (maternal absence, paternal absence, and sibling death) as predictors of menarcheal age in a well-characterized birth cohort born in 1983 in metropolitan Cebu, the Philippines. In this sample, which was marked by a near-absence of childhood overweight and obesity, we find that menarcheal age is not predicted by cues of risk and instability measured at birth and during childhood and early adolescence, but that infancy weight gain and measures of favorable childhood nutrition are strong predictors of maturational acceleration. These findings contrast with studies of populations in which psychosocial stress and instability co-occur with excess weight. The present findings suggest that infancy and childhood nutrition may exert greater influence on age at menarche than psychosocial cues in environments characterized by marginal nutrition, and that puberty is often delayed, rather than accelerated, in the context of stressful environments.  相似文献   

5.

Background

Age at sexual debut is a key behavioural indicator used in HIV behavioural surveillance. Early age at menarche may precipitate early sex through perceived readiness for sex, or through school drop-out, but this is rarely studied. We investigated trends and circumstances of sexual debut in relation to schooling and age at menarche.

Methods and Findings

A cross-sectional sexual behaviour survey was conducted on all individuals age 15–59 within a demographic surveillance site in Karonga District, Malawi. Time trends were assessed using birth cohorts. Survival analysis was used to estimate the median age at menarche, sexual debut and first marriage. The 25th centile was used to define “early” sex, and analyses of risk factors for early sex were restricted to those who had reached that age, and were done using logistic regression. Of the 8232 women and 7338 men resident in the area, 88% and 78%, respectively, were seen, and, 94% and 92% of these were interviewed. The median reported age at first sex was 17.5 for women and 18.8 for men. For women, ages at menarche, sexual debut and first marriage did not differ by birth cohort. For men, age at sexual debut and first marriage decreased slightly in later birth cohorts. For both men and women increased schooling was associated with later sexual debut and a longer delay between sexual debut and first marriage, but the associations were stronger for women. Earlier age at menarche was strongly associated with earlier sexual debut and marriage and lower schooling levels. In women early sexual debut (<16 years) was less likely in those with menarche at age 14–15 (odds ratio (OR) 0.31, 95%CI 0.26–0.36), and ≥16 (OR 0.04, 95%CI 0.02–0.05) compared to those with menarche at <14. The proportion of women who completed primary school was 46% in those with menarche at <14, 60% in those with menarche at 14–15 and 70% in those with menarche at ≥16. The association between age at menarche and schooling was partly explained by age at sexual debut. The association between age at menarche and early sex was not altered by adjusting for schooling.

Conclusions

Women with early menarche start sex and marry early, leading to school drop-out. It is important to find ways to support those who reach menarche early to access the same opportunities as other young women.  相似文献   

6.
Life history data, attractiveness ratings of male photographs, and attitudes towards partnership and child-rearing of 321 women were used to test four evolutionary models (quantitative reproductive strategy, male short-age, polygyny indication, and maternal reproductive interests) which attempt to explain the influence of family composition on reproductive strategies. Links between early menarche and other markers of reproductive strategy were investigated. Childhood stress and absence of a father figure, whether genetically related or not, were found to have accelerated menarche whereas having younger siblings decelerated it. Early menarche was associated with attractiveness ratings, the number of partners desired for the immediate future, and the early onset of intimate relationships. It was not linked with sociosexual orientation, mate choice criteria, and investment in the subjects’ own children, but these three markers were interrelated. The implications of the findings for the four evolutionary models are discussed.  相似文献   

7.
Life history theory suggests that in risky and uncertain environments the optimal reproductive strategy is to reproduce early in order to maximize the probability of leaving any descendants at all. The fact that early menarche facilitates early reproduction provides an adaptationist rationale for our first two hypotheses: that women who experience more risky and uncertain environments early in life would have (1) earlier menarche and (2) earlier first births than women who experience less stress at an early age. Attachment theory and research provide the rationale for our second two hypotheses: that the subjective early experience of risky and uncertain environments (insecurity) is (3) part of an evolved mechanism for entraining alternative reproductive strategies contingent on environmental risk and uncertainty and (4) reflected in expected lifespan. Evidence from our pilot study of 100 women attending antenatal clinics at a large metropolitan hospital is consistent with all four hypotheses: Women reporting more troubled family relations early in life had earlier menarche, earlier first birth, were more likely to identify with insecure adult attachment styles, and expected shorter lifespans. Multivariate analyses show that early stress directly affected age at menarche and first birth, affected adult attachment in interaction with expected lifespan, but had no effect on expected lifespan, where its original effect was taken over by interactions between age at menarche and adult attachment as well as age at first birth and adult attachment. We discuss our results in terms of the need to combine evolutionary and developmental perspectives and the relation between early stress in general and father absence in particular. This work was supported by The University of Melbourne Department of Obstetrics and Gynaecology. James S. Chisholm is Professor in the School of Anatomy and Human Biology at the University of Western Australia. He is an anthropologist whose interests lie in the fields of human behavioral biology, evolutionary ecology, life history theory, and parental investment theory, where he focuses on infant social-emotional development, the development of reproductive strategies, and the integration of evolutionary, developmental, and cultural psychology and public health. Julie A. Quinlivan is Associate Professor in Obstetrics and Gynaecology at the University of Melbourne and Head of the Maternity Care Program at the Royal Women’s Hospital, Melbourne. Her interests are teenage pregnancy, domestic violence, child abuse prevention, and high-risk pregnancy. Rodney W. Petersen is Senior Lecturer in Obstetrics and Gynaecology at the University of Melbourne and Senior Consultant in Obstetrics and Gynaecology at the Royal Women’s Hospital and Sunshine Hospital in Melbourne. His interests are in psychosocial aspects of women’s health and cancer. David A. Coall is a Ph.D. student in the School of Anatomy and Human Biology at the University of Western Australia. His main interest lies in the application of evolutionary theory within an epidemiological framework. He is currently working on the synthesis of life history theory, parental investment theory, and parent-offspring conflict theory in exploring factors that influence variation in human birth weight and placental weight.  相似文献   

8.
The relation between women's timing of menarche and father absence was examined in a national probability sample of Great Britain (NATSAL 2000; N>5000). Current body mass index (as a proxy for childhood weight) was examined as a potential mediator of this relationship, along with the potential moderating role that siblings (e.g. number of older brothers) had on this relationship. As in a number of previous studies, an absent father (but not an absent mother) during childhood predicted an earlier age of puberty (i.e. an early menarche). There was no evidence that weight mediated this relationship or that siblings moderated it. Both a lower body mass index and more siblings (e.g. more younger sisters and brothers) were independent predictors of a later timing of puberty. The results confirm that certain psychosocial factors (i.e. father absence; presence of siblings) may affect the timing of sexual maturation in adolescent girls.  相似文献   

9.
An evolutionary model of conditional reproductive strategies argues that girls whose fathers are absent or make little parental investment experience early puberty. However, such a conditional strategy cannot be adaptive unless the absence of the girl's father at the microlevel is predictive of some recurrent feature of the macrosocial system and early puberty is advantageous in the system. I argue that father absence is indicative of the degree of polygyny (simultaneous and serial) in society. Polygyny of both kinds creates a shortage of women in reproductive age, and thus, early puberty will be advantageous. Available comparative data indicate that the degree of polygyny is associated with a decrease in the mean age of menarche across societies, as is the divorce rate a presumptive index of serial polygyny, in strictly monogamous societies.  相似文献   

10.
Few studies have examined the role of early vs. later environment in the development of life history (LH) strategies, whether age at sexual debut mediates LH development, or whether LH indicators contribute to environmental stress in adulthood. In the current study, we addressed these gaps cross-culturally using data from Jenu Kurubas who live in the rural outskirts of Mysore (n = 133), India, and mixed-caste peri-urban residents in Mysore city (n = 222). Research took place from October 2016–July 2017. First, participants engaged in semi-structured interviews to formulate quantitative measures of current environmental stress (n = 60). Next, participants (n = 355) completed structured questionnaires that measured demographics; early and current environmental stress; and LH indicators including age at sexual debut, facets of impulsivity, education, and number of children. Structural equation modeling was used to test for the developmental cascade reported in Western studies of psychosocial acceleration (e.g., indirect effect of early environmental stress on number of children through age at sexual debut). Consistent with Western findings, environmental stress appeared to hasten sexual debut, decrease self-regulation and educational attainment, and increase current environmental stress in the peri-urban sample. Early environmental stress forecasted younger age at sexual debut in both samples; however, no other effects of early environmental stress nor any associations with current environmental stress were consistent between samples. Although age at sexual debut appeared to translate early environmental stress into greater numbers of children and current environmental stress in the peri-urban and rural samples, respectively, it was associated with different outcomes between the samples and forecasted adult environment only in the rural sample. Taken together, our findings indicate more research is needed to determine whether the developmental cascade suggested by most applications of LH theory to humans generalizes across cultures and rural and peri-urban environments.  相似文献   

11.
The assumption that the onset of puberty is a context-sensitive marker of a reproductive strategy is tested by comparing parental and filial childhood context and somatic development in West and East Germany. Sixty-eight mother-daughter dyads and 35 father-son dyads were taken from two samples of families from Osnabrück in West Germany and Halle in East Germany. According to the observed context discontinuity between the generations in the male dyads, linear regression models show that no indicator of male sexual maturation was influenced significantly by the somatic development of the father. Instead of an inherited timing of maturation, antecedent distal factors like socioeconomic childhood context variables and critical life events lead to an acceleration of male sexual maturation. Finally we test the effect of two different conditions of childhood context continuity on daughter’s age at menarche with maternal age at menarche controlled. Linear regression models show that mother’s age at menarche predicts daughter’s age at menarche only under the condition of contextual continuity between generations, which was the case in the West German sample only. In East Germany, where mother’s age at menarche had no significant effect, the amount of variance explained by childhood context variables was almost the same. These results indicate the context sensitivity of somatic development which seems to follow an evolutionary rationale.  相似文献   

12.
The reproductive histories and behavior of six chimpanzees were analyzed in order to evaluate the female reproductive pattern. This analysis indicated that captive females undergo an earlier menarche and an acceleration of subsequent reproductive phases as compared to wild chimpanzees. Menarche occurred between 7.7–9.3 years of age and first conceptions occurred between 8.2–10.7 years of age. Changes in the females' sex skins across menarche, pregnancy, and the menstrual cycle were also evaluated. The fluctuation in sex skin size was shown to have a marked effect on the occurrence of sexual behavior. In addition, the social context and relative familiarity of the chimpanzees affected the choice of sexual partners.  相似文献   

13.
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.  相似文献   

14.
Age at first intercourse   总被引:1,自引:0,他引:1  
In 1984-85 a representative sample of 286 Danish women and 336 men aged 16-20 years were interviewed about their sexual debut. Seventy-four females (25.9%) and 101 males (30.1%) had not yet experienced sexual intercourse. A maximum likelihood estimation method was used to establish the age distribution at sexual debut. This takes into account knowledge of age at interview among the non-experienced respondents and of the few who did not report age at sexual debut. The median age at first sexual intercourse was close to 16.8 years for both females and males. This appeared to be a consequence of age at debut declining among women and remaining unchanged among males during the preceding 20 years.  相似文献   

15.
Early life factors are associated with the timing of reproductive events in adolescence, but a variety of hypotheses (such as psychosocial acceleration theory, paternal investment theory, extrinsic mortality, internal prediction, and intergenerational conflict) propose different explanations for why this may occur. To compare between these theories, we use the National Longitudinal Survey of Children and Youth, an extensive, longitudinal survey of Canadian male and female youth (aged 14-15 in last wave) to identify variables that uniquely support these different models (n≈1200). We identify the best predictors of sexual initiation for each hypothesis and then use a model selection procedure to determine which set of variables has the most support. Results show that variables representing extrinsic mortality cues, intergenerational conflict, early life psychosocial stressors, and prenatal factors are included in the top models, while variables representing social support and unpredictability are represented in some of the top models. Variables representing the paternal investment theory were not included in any of the top models, suggesting limited support for this hypothesis. These results support many of the hypotheses that have been previously presented in the literature, suggesting that timing of sexual initiation may have multiple causal pathways.  相似文献   

16.
This paper examines the effects of three different types of father absence on the timing of life history events among women in rural Bangladesh. Age at marriage and age at first birth are compared across women who experienced different father presence/absence conditions as children. Survival analyses show that daughters of fathers who divorced their mothers or deserted their families have consistently younger ages at marriage and first birth than other women. In contrast, daughters whose fathers were labor migrants have consistently older ages at marriage and first birth. Daughters whose fathers died when they were children show older ages at marriage and first birth than women with divorced/deserted fathers and women with fathers present. These effects may be mediated by high socioeconomic status and high levels of parental investment among the children of labor migrants, and a combination of low investment, high psychosocial stress, and low alloparental investment among women with divorced/deserted fathers. Our findings are most consistent with the Child Development Theory model of female life history strategies, though the Paternal Investment and Psychosocial Acceleration models also help explain differences between women in low paternal investment situations (e.g., father divorced/abandoned vs. father dead). Father absence in and of itself seems to have little effect on the life history strategies of Bangladeshi women once key reasons for or correlates of absence are controlled, and none of the models is a good predictor of why women with deceased fathers have delayed life histories compared with women whose fathers are present.  相似文献   

17.
Among the population of the Krummhörn region (Ostfriesland, Germany) in the 18th and 19th centuries, the death of the father in the family led on average to the accelerated marriage of his children. Three evolutionary explanations are offered for this “paternal absence” effect in the literature: namely, (i) the assumption of an adaptive “psychosocial acceleration” of the children with prepubertal experience of uncertainty; (ii) an opportunistic adjustment of life and reproduction decisions as an adaptive reaction to the personal cost–benefit balances that are changed by the father's death; and (iii) given the genetic parent–offspring conflict, an increase in the reproductive autonomy of offspring after the loss of the dominant father figure. Our models, which are based on the analyses of the vital statistics data derived from church registers and tax rolls and compiled into a family reconstitution study, attribute the greatest explanatory power for the patterns found in the Krummhörn to the opportunistic adjustment approach (ii).  相似文献   

18.
19.
Menopause is associated with the general ageing process and marks the end of follicular depletion, a process that begins in the intrauterine stage and lasts throughout the lifetime of women until their reproductive senescence. Controversy persists about whether the age at menopause is sensitive to the ecological determinants prevailing during the lifecycle or whether it has a predominantly genetic component that would allow groups of women to be characterized with respect to particular menstrual characteristics manifested throughout their fertile life. By contrast, there is a definite secular trend in age at menarche in populations that have registered improvements in their environment: sexual maturation is closely associated with the general processes of growth and development. These aspects were analysed in a sample of Spanish women, mothers and daughters, born between 1883 and 1941. The results show (a) indications--although not conclusive--of a secular trend in the age at menopause, (b) a possible association between the age at menopause of mothers and their daughters, and (c) an association at the individual level between age at menarche, particular characteristics of ovarian function (fetal loss) and age at menopause. The reproductive ageing process therefore seems to result from the expression of the influence of ecological conditions in which the lifecycle of the women develops and of a degree of heritability that affects not only the age at menopause but also a range of characteristics of ovarian function.  相似文献   

20.
There is considerable variation in health and reproductive behaviours within and across human populations. Drawing on principles from Life History Theory, psychosocial acceleration theory predicts that individuals developing in harsh environments decrease their level of somatic investment and accelerate their reproductive schedule. Although there is consistent empirical support for this general prediction, most studies have focused on a few isolated life history traits and few have investigated the way in which individuals apply life strategies across reproductive and somatic domains to produce coordinated behavioural responses to their environment. In our study, we thus investigate the impact of childhood environmental harshness on both reproductive strategies and somatic investment by applying structural equation modeling (SEM) to cross-sectional survey data obtained in a representative sample of the French population (n = 1015, age: 19–87 years old, both genders). This data allowed us to demonstrate that (i) inter-individual variation in somatic investment (e.g. effort in looking after health) and reproductive timing (e.g. age at first birth) can be captured by a latent fast-slow continuum, and (ii) faster strategies along this continuum are predicted by higher childhood harshness. Overall, our results support the existence of a fast-slow continuum and highlight the relevance of the life history approach for understanding variations in reproductive and health related behaviours.  相似文献   

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