Two samples of male students (N = 25, and N = 51) and a small sample of female students (N = 7) were administered the Sensation Seeking Scale (SSS), and blood samples were drawn on two occasions to determine plasma levels of androgens and oestrogens. Reliable and significant simple and partial correlations were found between the sex hormones and the SSS subscale, Disinhibition. Partial correlations simultaneously controlled for height, weight, age, and recency of orgasm.

Demographic data on fertility and intermarriage are useful measures of integration and assimilation. This paper reviews trends in total fertility and intermarriage of foreign populations in Europe and compares them with the trends in fertility of the host population and the sending country. In almost all cases fertility has declined. The fertility of most European immigrant populations and of some West Indian and non-Muslim Asian populations has declined to a period level at or below that of the host society. Muslim populations from Turkey, North Africa and South Asia have shown the least decline. Intermarriage is proceeding faster than might be expected in immigrant populations which seemed in economic terms to be imperfectly integrated. Up to 40% of West Indians born in the UK, for example, appear to have white partners as do high proportions of young Maghrebians in France.

This paper elaborates the hypothesis that the unique demography and sociology of Ashkenazim in medieval Europe selected for intelligence. Ashkenazi literacy, economic specialization, and closure to inward gene flow led to a social environment in which there was high fitness payoff to intelligence, specifically verbal and mathematical intelligence but not spatial ability. As with any regime of strong directional selection on a quantitative trait, genetic variants that were otherwise fitness reducing rose in frequency. In particular we propose that the well-known clusters of Ashkenazi genetic diseases, the sphingolipid cluster and the DNA repair cluster in particular, increase intelligence in heterozygotes. Other Ashkenazi disorders are known to increase intelligence. Although these disorders have been attributed to a bottleneck in Ashkenazi history and consequent genetic drift, there is no evidence of any bottleneck. Gene frequencies at a large number of autosomal loci show that if there was a bottleneck then subsequent gene flow from Europeans must have been very large, obliterating the effects of any bottleneck. The clustering of the disorders in only a few pathways and the presence at elevated frequency of more than one deleterious allele at many of them could not have been produced by drift. Instead these are signatures of strong and recent natural selection.

The Lese are subsistence farmers living in the Ituri Forest of north-east Zaïre. They exhibit significant birth seasonality, with lowest frequencies of conception when food production is least, nutritional status is low and ovarian function, as measured by salivary steroid hormone levels, is reduced. Efe pygmy foragers, who live in the same geographical area but are less dependent on cultivated foods and have a more flexible life style, do not exhibit frequent fluctuations in nutritional status nor significant birth seasonality. These findings support a model of birth seasonality relating climatic variables to variation in fertility through a causal chain linking rainfall to food production to energy balance to ovarian function to fertility. The model, which emphasises an ecological approach to the study of human reproduction, should have broad applicability since seasonality of food production and energy balance is widespread geographically and across a wide variety of economies and cultures.

A strong case has recently been made by academics and policymakers to develop national programmes for the integrated control of Africa’s ‘neglected tropical diseases’. Uganda was the first country to develop a programme for the integrated control of two of these diseases: schistosomiasis and soil-transmitted helminths. This paper discusses social responses to the programme in Panyimur, north-west Uganda. It shows that adults are increasingly rejecting free treatment. Resistance is attributed to a subjective fear of side-effects; divergence between biomedical and local understandings of schistosomiasis/bilharzia; as well as inappropriate and inadequate health education. In addition, the current procedures for distributing drugs at a district level are problematic. Additional research was carried out in neighbouring areas to explore the generalizability of findings. Comparable problems have arisen. It is concluded that the national programme will not fulfil its stated objectives of establishing a local demand for mass treatment unless it can establish more effective delivery strategies and promote behavioural change in socially appropriate ways. To do so will require new approaches to social, economic and political aspects of distribution. There are reasons why populations infected with the ‘neglected tropical diseases’ are themselves neglected. Those reasons cannot just be wished away.

This paper conceptualises the motive force behind human childbearing as originating in two broad traits which have biological bases, are shaped by experiences during early life and are expressed through their effect on desires and intentions. An instrument for measuring childbearing motivation, the Childbearing Questionnaire (CBQ), is presented. Using a sample of 401 married couples two main scales, nine subscales, and several independent items are described. Evidence for the reliability and validity of this instrument is presented. The versatility of the CBQ as a research instrument and the usefulness of the conceptualisation from which it is derived as a way of integrating social, behavioural, and biological science approaches to childbearing motivation are discussed.

The aim of this paper was to stress the importance of the adaptive cognitive functioning of man in the causation of prejudice. It was felt that this approach has the merits of economy, credibility and testability of explanation which are not always shared by views seeking the psychological causes of intergroup tensions in the evolutionary past of the species or in unconscious motivation. Three cognitive processes were considered from the point of view of their relevance to the genesis of prejudice in an individual: categorization, assimilation, and search for conceptual coherence.

Though the paper was not concerned either with discussing ways to reduce prejudice or with outlining in any detail designs for future research, it is my belief that the general approach adopted here has implications, both for social action and for research, which have not been as yet consistently and fully taken into account.

Annual changes in twinning and triplet rates by zygosity were investigated in eight countries during the period 1972–1999 using vital statistics. The monozygotic (MZ) twinning rates in Denmark, Switzerland and the Slovak Republic remained more or less constant throughout this period, whereas those in England and Wales, the Federal Republic of Germany (Germany), the Netherlands, the Czech Republic and Japan increased significantly year by year. With the exception of the Slovak Republic, the dizygotic (DZ) twinning rate increased significantly year by year in each country. It was 2·9 times higher in Denmark and 1·5 times higher in Germany in 1999 than in 1972, and within the same range in the other countries. With two exceptions, the MZ triplet rates remained more or less constant in each country. On the other hand, the DZ and trizygotic (TZ) triplet rates increased significantly year by year in each country. The TZ rate increased 30-fold in Germany, 16·6-fold in Japan, 11·7-fold in Switzerland, 9·7-fold in the Czech Republic, 8·7-fold in the Netherlands, 6·4-fold in Denmark, 5·6-fold in England and Wales and 3·5-fold in the Slovak Republic. The higher DZ twinning rate and higher DZ and TZ triplet rates since 1983 have been attributed to the higher proportion of mothers being treated with ovulation-inducing hormones and in vitro fertilization (IVF) in Denmark, England and Wales, Germany, the Netherlands, Switzerland and Japan. After the introduction of fertility drugs and IVF, variations in the DZ twinning and triplet rates and the TZ triplet rates were not only due to biological factors, but also depended on the popularity of fertility drugs and IVF in each country. In the Slovak Republic, where human fertility might not be affected by some adverse environmental factors, the DZ:MZ ratio remained constant during the period 1972–1999.

The proximate causes of the contraceptive effect of lactation are still a matter of productive debate. This study sought to disentangle the relative impact that intense breast-feeding practices and maternal nutrition have on the regulation of ovarian function in nursing women. A mixed-longitudinal, direct-observational, prospective study was conducted of the return to postpartum fecundity in 113 breast-feeding, well-nourished Toba women. A sub-sample of 70 women provided data on nursing behaviour, daily activities, diet quality and urinary levels of oestrone and progesterone metabolites. Well-nourished, intensively breast-feeding Toba women experienced a relatively short period of lactational amenorrhoea (10·2±4·3 months) and a high lifetime fertility (TFR=6·7 live births/woman). Duration of lactational amenorrhoea was not correlated with any of the nursing parameters under study or with static measures of maternal nutritional status. The results indicated that the pattern of resumption of postpartum fertility could be explained, at least partly, by differences in individual metabolic budgets. Toba women resumed postpartum ovulation after a period of sustained positive energy balance. As the relative metabolic load hypothesis suggests, the variable effect of lactation on postpartum fertility may not depend on the intensity of nursing per se but rather on the energetic stress that lactation represents for the individual mother.

The majority of studies of the birth spacing–child survival relationship rely on retrospective data, which are vulnerable to errors that might bias results. The relationship is re-assessed using prospective data on 13,502 children born in two Nairobi slums between 2003 and 2009. Nearly 48% were first births. Among the remainder, short preceding intervals are common: 20% of second and higher order births were delivered within 24 months of an elder sibling, including 9% with a very short preceding interval of less than 18 months. After adjustment for potential confounders, the length of the preceding birth interval is a major determinant of infant and early childhood mortality. In infancy, a preceding birth interval of less than 18 months is associated with a two-fold increase in mortality risks (compared with lengthened intervals of 36 months or longer), while an interval of 18–23 months is associated with an increase of 18%. During the early childhood period, children born within 18 months of an elder sibling are more than twice as likely to die as those born after an interval of 36 months or more. Only 592 children experienced the birth of a younger sibling within 20 months; their second-year mortality was about twice as high as that of other children. These results support the findings based on retrospective data.

This study examines the trends and determinants of child marriage among women aged 20–49 in Bangladesh. Data were extracted from the last six nationally representative Demographic and Health Surveys conducted during 1993–2011. Simple cross-tabulation and multivariate binary logistic regression analyses were adopted. According to the survey conducted in 2011, more than 75% of marriages can be categorized as child marriages. This is a decline of 10 percentage points in the prevalence of child marriage compared with the survey conducted in 1993–1994. Despite some improvements in education and other socioeconomic indicators, Bangladeshi society still faces the relentless practice of early marriage. The mean age at first marriage has increased by only 1.4 years over the last one and half decades, from 14.3 years in 1993–1994 to 15.7 years in 2011. Although the situation on risk of child marriage has improved over time, the pace is sluggish. Both the year-of-birth and year-of-marriage cohorts of women suggest that the likelihood of marrying as a child has decreased significantly in recent years. The risk of child marriage was significantly higher when husbands had no formal education or little education, and when the wives were unemployed or unskilled workers. Muslim women living in rural areas have a greater risk of child marriage. Women's education level was the single most significant negative determinant of child marriage. Thus, the variables identified as important determinants of child marriage are: education of women and their husbands, and women's occupation, place of residence and religion. Programmes to help and motivate girls to stay in school will not only reduce early marriage but will also support overall societal development. The rigid enforcement of the legal minimum age at first marriage could be critical in decreasing child marriage.

This study explores the prevalence and factors associated with the utilization of maternal and child health care services among married adolescent women in India using the third round of the National Family Health Survey (2005–06). The findings suggest that the utilization of maternal and child health care services among adolescent women is far from satisfactory in India. A little over 10% of adolescent women utilized antenatal care, about 50% utilized safe delivery services and about 41% of the children of adolescent women received full immunization. Large differences by urban–rural residence, educational attainment, religion, economic status and region were evident. Both gross effect and fixed effect binary logit models yielded statistically significant socioeconomic and demographic factors. Women's education, wealth quintile and region are the most important determinants for the utilization of maternal and child health care services. Health care programmes should focus more on educating adolescents, providing financial support, creating awareness and counselling households with married adolescent women. Moreover, there should be substantial financial assistance for the provision of delivery and child care for married women below the age of 19 years.

Consanguineous marriage is traditionally common throughout Arab countries. This leads to an increased birth prevalence of infants with recessive disorders, congenital malformations, morbidity and mortality. The aim of this study was to evaluate the rate of consanguineous marriage in families with autosomal recessive diseases, and to compare it with the average rate of consanguinity in the Moroccan population. The study was conducted in the Department of Medical Genetics in Rabat on 176 families with autosomal recessive diseases diagnosed and confirmed by clinical, radiological, enzymatic or molecular investigations. The rate of consanguinity was also studied in 852 families who had infants with trisomy 21 confirmed by karyotyping. These families were chosen because: (i) there is no association between trisomy 21 and consanguinity, (ii) these cases are referred from different regions of Morocco and (iii) they concern all social statuses. Among 176 families with autosomal recessive disorders, consanguineous marriages comprised 59.09% of all marriages. The prevalence of consanguinity in Morocco was found to be 15.25% with a mean inbreeding coefficient of 0.0065. The differences in the rates of consanguineous marriages were highly significant when comparing the general population and couples with offspring affected by autosomal recessive conditions. These results place Morocco among the countries in the world with high rates of consanguinity. Autosomal recessive disorders are strongly associated with consanguinity. This study better defines the health risks associated with consanguinity for the development of genetic educational guidelines targeted at the public and the health sector.

This study examines the frequency of consanguineous marriage and coefficient of inbreeding in the State of Qatar. The study was conducted in semi-urban areas of Doha between January and May 2004. A sample of 1515 married Qatari females aged 15 years and over participated. The degree of consanguinity between each female and her spouse, and degree of consanguinity between their parents were recorded. The rate of consanguinity in the present generation was high (54·0%) with a coefficient of inbreeding of 0·02706. The commonest type of consanguineous marriage was between first cousins (34·8%). Double first cousin marriages were common (3·1%) compared with other populations. The consanguinity rate in the State of Qatar has increased from 41·8% to 54·5% in one generation.

Data from an urban sample of American women of reproductive ages demonstrate that age at menarche is correlated with age at first intercourse, that age at first intercourse is correlated with age at first pregnancy, and that age at menarche is therefore correlated with age at first pregnancy. This applies to both blacks and whites when examined for the early years of the reproductive cycle. Girls with early menarche, compared to those with late menarche, are more than twice as likely to have had intercourse by age 16, and almost twice as likely to have given birth or had a pregnancy terminated by age 18. It is therefore useful to think of the timing of meanarche as an indicator of the probability of early intercourse and early childbearing.

This study examines the reproductive success of men and women in rural Ethiopia as a function of their marital status, specifically by comparing polygamously and monogamously married individuals. In line with predictions from evolutionary theory, polygamy is beneficial to male reproductive success (i.e. producing larger numbers of surviving offspring). The success of polygamously married females depends on wife rank: the first wives of polygamous husbands do better than monogamously married women and much better than second or third wives. These effects are mirrored in child nutritional status: the children of second and third wives have lower weight for height. Due to potential, largely unmeasurable differences in marriageability (quality) between individuals, it was not possible to support a model of either resource-holding polygyny combined with female choice or female coercion into unwanted marriages. First wives of polygamously married men marry at a younger age and attract a higher brideprice, suggesting that both the males and females in the marriage are likely to be of higher quality (due to wealth, family status or some other factor such as beauty). Unions that end up monogamous are likely to be between slightly lower quality individuals; and second and third wives, who marry at the oldest ages and attract the lowest brideprice, may be ‘making the best of a bad job’. The relatively long gap between first and second marriages may mean that first wives of highly marriageable males can enjoy considerable reproductive success before their husbands marry again.

The current surge in childlessness is often seen as an alternative lifestyle amidst growing pluralism and individualism. The results of this study indicate that several subgroups of childless women need to be differentiated: those who actively decide to forgo children in favour of other life pursuits and those who merely defer the decision. Both have accumulated a high degree of human capital in their education or career-building paths. Thus, the increase of a woman's time invested in education or career formation takes its toll on the time available for childrearing. A survey performed among female academics (N=193) brought to light that among childless women, many merely mean to postpone motherhood until their career prospects are established. Differences between those who outwardly reject motherhood and those who defer the decision can be seen in a variety of job- and career-related aspects. However, due to misconceptions about fertility, many of those who merely intended to postpone children may inevitably end up ‘involuntarily childless’. As this trend is most likely to increase in the near future, the resolution of this conflict will be an important milestone in the development of modern industrialized countries. As can be seen from this survey, financial benefits will not induce women to enter into motherhood. Rather, societal and infrastructural changes have to be brought about in order to induce women to enter into motherhood.

Literature on the subject of the menopause, primarily from the past three decades, is selectively reviewed in the form of an annotated bibliography. In order to highlight particular methodological problems, the review is presented in three sections, each preceded by a brief discussion, as follows: (a) the general report of clinical observation or experience, (b) the survey, and (c) the clinical trial. Several recommendations are also made for further research in this field.

To summarize the findings presented here, only three of the five factors studied appear to be independently related to the sex ratio at birth. The significant negative birth-order effect, which in the first analysis accounted for a 2·6% shift in the relative odds of male birth, remained significant when adjustment for the race effect was provided in the second analysis. The magnitude of the effect was diminished by this adjustment, however, indicating that analysis for birth-order effects in the absence of adjustment for the race factor may lead to over-estimates of the importance of the birth-order factor.

The significant race effect detected in the second analysis resulted in a 3% lower relative odds for a Negro male birth than that for a white. This racial difference, coupled with the non-uniform distribution of Negro births by paternal-age and birth-order categories, appears to be the source of the mysterious ‘interactioneffect’ between birth order and paternal age reported by Novitski & Kimball. The race effect remained significant after adjustment was provided for both the birthorder and socio-economic effects.

Skilled attendance at delivery is one of the key indicators to reflect progress toward the Millennium Development Goal of improving maternal health. This paper assesses global progress in the use of skilled attendants at delivery and identifies factors that could assist in achieving Millennium Development Goals for maternal health. National data covering a substantial proportion of all developing country births were used for the estimation of trends and key differentials in skilled assistance at delivery. Between 1990 and 2000, the percentage of births with a skilled attendant increased from 45% to 54% in developing countries, primarily as a result of an increasing use of doctors. A substantial proportion of antenatal care users do not deliver with a skilled attendant. Delivery care use among antenatal care users is highly correlated with wealth. Women aged 35 and above, who are at greatest risk of maternal death, are the least likely to receive professional delivery care. Births in mid-level facilities appear to be a strategy that has been overlooked. More effective strategies are needed to promote skilled attendance at birth during antenatal care, particularly among poor women. Specific interventions are also needed to encourage older and high parity mothers to seek professional care at delivery.