During the first half of this century, the seasonal pattern of births in European countries showed a major peak in the spring and a minor peak in the autumn. In contrast, the pattern in the US was of a minor peak in spring and a major peak in autumn. Over the last 20 years, the pattern in England and Wales has changed to resemble the US pattern, and the same seems to be true of several other European countries. A hypothesis is offered to account for the difference between the European and the US patterns and for the change from one to the other in some countries.

The magnitude of seasonality correlates positively with latitude: it is suggested that this is partially consequent on variation in luminosity.

To examine the effects of birth spacing on early childhood mortality, 3729 singleton births in 1983–84 were followed for 3 years in rural Bangladesh. Logistic regression analyses were used to assess whether the survival of older siblings modifies the effect of preceding birth intervals and to see if the effects of preceding and succeeding birth intervals are inter-related, controlling for the effects of sex of the child, mother's age and household economic status. With the exception of the neonatal period, birth spacing effects were highly significant. A preceding birth interval of <15 months was associated with a greater mortality risk in the post-neonatal period for children with an older sibling who survived infancy. However, a short preceding birth interval did not adversely affect post-neonatal mortality if the older sibling died in infancy. Neonatal and post-neonatal deaths were higher if older siblings had died in respective age intervals. A pregnancy interval of <12 months after childbirth raised the risk of death at ages 1–2 years considerably if the child was born after a short birth interval (<15 months). The results suggest that the high mortality risks of closely spaced children are due to sibling competition for parental resources.

Homosexual men have a higher mean birth order than do heterosexual men, primarily because they have a greater number of older brothers. The purpose of this study was to determine whether the same difference occurs in homosexual vs heterosexual women. The probands were 964 homosexual and heterosexual, male and female volunteers, from whom birth order data were collected with self-administered questionnaires. The homosexual men had more older brothers than the heterosexual men, but they did not have more older sisters, younger brothers, or younger sisters. The homosexual women did not differ from the heterosexual women with regard to any class of sibling. These results are consistent with the hypothesis that the high birth order of homosexual men reflects the progressive immunization of certain mothers to H-Y antigen by succeeding male fetuses, and the increasing effects of H-Y antibodies on sexual differentiation of the brain in succeeding male fetuses.

Understanding care-seeking practices and barriers to prevention of mother-to-child transmission (PMTCT) of HIV is necessary in designing effective programmes to address the high disease burden due to HIV/AIDS in Uganda. This study explored perceptions, care-seeking practices and barriers to PMTCT among young and HIV-positive women. A household survey (10,706 women aged 14–49 years), twelve focus group discussions and 66 key informant interviews were carried out between January and April 2009 in Wakiso district, central Uganda. Results show that access to PMTCT services (family planning, HIV counselling and testing and delivery at health units) was poor. Decision making was an important factor in accessing PMTCT services. Socioeconomic factors (wealth quintile, age, education level) and institutional practices also influenced access to PMTCT. Overall, having had an HIV test was highest when both men and women made decisions together or when women were empowered to make their own decisions. This was significant across wealth quintiles (p=0.0001), age groups (p=0.0001) and education levels (p=0.0001). The least level of HIV testing was when men made decisions for their spouses; and this was the case with family planning and deliveries at health units. Other barriers to PMTCT were fear of women and male spouses to have an HIV test and the perception that HIV testing is compulsory in antenatal clinics. In conclusion, to increase access to PMTCT among women, especially the young, poor and least educated, there is a need to empower them to make decisions on health seeking, and also to empower men to support their spouses to make good decisions. Other barriers like fear of having an HIV test should be addressed through appropriate counselling of clients.

Worldwide, there is increasing recognition that if family and reproductive health programmes are to be successful, the involvement of men is essential. As part of the problem, men also have to be seen as part of the solution. The reality is that in many countries, including Turkey, men generally do not accompany their partners to health facilities for family planning, antenatal and postnatal services and are not expected to attend the labour or birth of their child. Workplace programmes are a potential strategy for meeting the reproductive health education needs of men in industrial cities such as Istanbul. This intervention study was developed to test the feasibility and effects of expanding a special programme for expectant fathers to large workplaces in Istanbul, with the aim of improving the health of Turkish families during the pregnancy, birth and newborn periods. The findings indicate that it is possible to train workplace physicians in Istanbul to conduct regular educational programmes for expectant fathers on reproductive health, and that such programmes may have beneficial effects, especially in the areas of pregnancy nutrition, exclusive breast-feeding, and support behaviours. Considering the difficulty of getting men to attend hospital or clinic-based educational programmes in large urban areas, bringing such training programmes to men at their places of work has the potential to be an important strategy. Given that large workplaces in Turkey already have full-time physicians charged with the duty of health education for employees, this is also a feasible strategy.

Birth weight is known to be closely related to child health, although as many infants in developing countries are not weighed at birth and thus will not have a recorded birth weight it is difficult to use birth weight when analysing the determinants of child illness. It is common to use a proxy for birth weight instead, namely the mother's perception of the baby's size at birth. Using DHS surveys in Cambodia, Kazakhstan and Malawi the responses to this question were assessed to indicate the relationship between birth weight and mother's perception. The determinants of perception were investigated using multilevel ordinal regression to gauge if they are different for infants with and without a recorded birth weight, and to consider if there are societal or community influences on perception of size. The results indicate that mother's perception is closely linked to birth weight, although there are other influences on the classification of infants into size groups. On average, a girl of the same birth weight as a boy will be classified into a smaller size category. Likewise, infants who died by the time of the survey will be classified as smaller than similarly heavy infants who are still alive. There are significant variations in size perception between sampling districts and clusters, indicating that mothers mainly judge their child for size against a national norm. However, there is also evidence that the size of infants in the community around the newborn also has an effect on the final size perception classification. Overall the results indicate that mother's perception of size is a good proxy for birth weight in large nationally representative surveys, although care should be taken to control for societal influences on perception.

Many Bangladeshi women marry early, and many marry before the legal age of 18 years. This practice has been associated with a higher risk of health and medical morbidities, and also early pregnancy with higher pre- and postnatal complications. The aim of this study was to determine the prevalence, and factors associated with, child marriage among Bangladeshi women using multiple binary logistic regression analysis of data from the BDHS-2011. Further analysis on the trend of age at first marriage was performed with additional data sets from previous surveys. The mean and median of ages at first marriage of Bangladeshi women in 2011 were 15.69±2.97 and 15.00 years, respectively. A remarkably high percentage (78.2%) married before the age of 18; of these, 5.5% married at a very early age (before 13 years of age). Binary logistic regression analysis demonstrated that uneducated women were more likely to be married early (p<0.001) than those with secondary and higher education. Child marriage was especially pronounced among women with uneducated husbands, Muslims, those with poor economic backgrounds and those living in rural areas. Further analysis including data from previous BDHS surveys showed that child marriage among Bangladeshi women had a decreasing trend from 1993–94 to 2011. These results show that child marriage was very common in Bangladesh, and closely associated with low level of education and low economic status. The decreasing trend in child marriage indicates an improvement over the past two decades but more effort is needed to further reduce and eventually eliminate the practice.

In a sample of 282 marriages in New Nubia in Egypt, 39% were between first cousins and 21% between less closely related kin. The average number of liveborn offspring in first-cousin marriages was higher than in marriages between more distant relations and unrelated spouses, but the number of deaths among children of first-cousin couples was also higher.

This study aimed to contribute to the evidence on the timing of sexual debut in young people in sub-Saharan African countries. Data were extracted from 34 nationally representative surveys conducted in the region between 2006 and 2014. The study sample comprised unmarried women (n=167,932) and men (n=76,900) aged 15–24 years. Descriptive techniques and Cox proportional regression models were used to estimate the timing of sexual debut, and Kaplan–Meier hazard curves were used to describe the patterns of sexual debut in each country by sex. For the countries studied, sexual debut for both women and men occurred between the ages of 15 and 18 years, with median ages of 16 for women and 17 for men. Overall, education and household wealth provided significant protection against early sexual debut among women, but the reverse was found among men for wealth. Women in rural areas, in female-headed households and in Central, South and West Africa reported higher hazards of early commencement of sexual activity than their counterparts in urban, male-headed households and East Africa. However, the impact of these variables on male sexual debut did not follow a consistent pattern. Varied timing, as well as country-specific risk factors associated with sexual debut for young women and men across sub-Saharan Africa, were identified. Sexual health programmes and interventions for young people may require different approaches for young women and men.

The aim of this paper is to account for the effect of mother's death on child survival in a historical population. Using comprehensive data on the early French Canadian population of Quebec, evidence is provided for a higher risk of dying for motherless children that remains significant over all childhood and long after the death of the mother. The specific effect of the loss of maternal care was estimated by comparing mortality before and after mother's death, furnishing a means to control for family heterogeneity. No differential in investment between genders was detected before age 3, but older girls suffered a three-fold higher susceptibility to mother's death than their male counterparts. This suggests that grown-up girls assuming the responsibilities of the missing mother had a lower chance of survival.

This study tests two evolutionary hypotheses on grandparental investments differentiated by the child's sex: the paternity uncertainty hypothesis and the Trivers–Willard hypothesis. Data are from two culturally different countries: the Dutch Longitudinal Aging Study Amsterdam (n=2375) and the Chinese Anhui Survey (n=4026). In the Netherlands, grandparental investments are biased towards daughters' children, which is in accordance with the paternity uncertainty hypothesis. But in China, grandparental investments are biased towards sons' children, which is in conflict with the paternity uncertainty hypothesis. This study found no support for the Trivers–Willard hypothesis. These results raise doubts over the relevance of paternity uncertainty as an explanation of a grandparental investment bias towards daughters' children that is often found in Western populations. The results suggest that discriminative grandparental investments are better understood as the outcome of cultural prescriptions and economic motives.

In January 1985, a Gallup poll sponsored by the American College of Obstetrics and Gynecologists reported that 76% of the US women sampled thought that there were substantial risks with using the pill, 31% thought the pill caused cancer and 64% thought the risk of childbearing was equal to or less than that in taking the pill. To assess the perceptions of the pill's safety internationally, a survey of 100–150 urban, middle-class women aged 18–45 years was conducted in each of eight countries in the developing world. There were striking similarities in perceptions of the pill's health effects between countries: (1) taking the pill is considered to have substantial health risks by 50–75% and is thought to be more hazardous than childbearing by over 40% of respondents except those in the African samples; (2) women who had used the pill are as unaware as those who had not of possible serious cardiovascular adverse effects; (3) the protective effects of the pill are virtually unknown; (4) the greatest inconsistency with scientific evidence concerns the risks of sterility and birth defects attributed to pill use. With information from this survey, family planning programmes can rectify almost universal misperceptions of the pill's safety when counselling new and continuing pill users.

Data from the final 16 years of a 28-year ongoing survey of menarcheal age are reported. From 1971 onwards, recalled aged at menarche was recorded for all young women entering the University of Warwick. These data show that mean menarcheal age is increasing, a trend which is independent of father's occupation, family size, position of girl in the family, and physique. This continues a similar upward tendency noted in a preceding study in Swansea. It appears that the downward trend to earlier age at menarche of the earlier decades of this century has been replaced by one in the opposite direction.

On 26th December 2003, a severe earthquake hit the city of Bam in Kerman province, southern Iran. It destroyed around 90% of houses and at least 60% of the public buildings, and claimed the lives of more than 20,000 persons. To investigate whether acute stress caused by the Bam earthquake could alter the sex ratio at birth (SRB) 6–12 months later, the present study was done. The number of live births by sex was obtained from the National Organization for Civil Registration (Kerman province). The SRB was expressed as the male proportion. A prominent decline in the SRB (̃0·467) 11 months after the earthquake was observed (χ2=6·68, df=1, p=0·009). There was no significant difference between Bam and Kerman province (excluding Bam) for SRB (χ2=0·44, df=1, p=0·51) for a period of 33 month before the earthquake (from April 2001 to December 2003). It might be concluded that psychological tensions and stress are associated with a decrease in SRB.

The study analyses various sex differences observed among children in WFS and DHS surveys conducted in sub-Saharan Africa. Four outcome indicators are presented: neonatal mortality, postneonatal mortality, child mortality and prevalence of malnutrition. Three indicators of health seeking behaviour are presented: vaccination, oral rehydration therapy and duration of breast-feeding. The statistical analysis focuses on comparison of the observed distributions of the sex ratios to theoretical distributions expected from the sample sizes of the various surveys. The results show the absence of any difference in health seeking behaviour between boys and girls, whether for preventive medicine (vaccination), curative medicine (oral rehydration therapy) or feeding practices (breast-feeding). On the other hand, mortality appears to be consistently higher for boys, more so among neonates (+28%) than among 1–12-month-olds (+8%) and 1–4-year-olds (+4%), and similarly malnutrition appears to be more prevalent among boys (+5%). The contrast between the lack of differences in behavioural indicators and the significant differences in outcome indicators suggests a biological causality. Results are discussed in the light of biological factors.

This study was carried out by the Turkish Republic Ministry of Health to determine the prevalence of consanguineous marriage and its correlates with socio-demographic and obstetric risk factors in women in Turkey. The cross-sectional, national-level study was carried out from October to December 2013. The study population was composed of women between the ages of 15 and 65 years living in Turkey. The sample size was calculated as 9290 houses within Turkey’s 81 provinces so as to improve the Turkish rural–urban expectations by means of systematic stack sampling according to the Turkish Statistical Institute’s address-based vital statistics system. The target sample size was 6364, but only eligible 4913 women, who had been married, were included in the study. The consanguineous marriage frequency in the sample was found to be 18.5%, and of these 57.8% were first cousin marriages. Women living in an extended family and whose education level and first marriage ages were low, and whose perceived economic status was poor, had higher frequencies of consanguineous marriage (p<0.001). Consanguineous marriage frequencies were higher (p<0.001) for women who had spontaneous abortions and stillbirths or who had given birth to infants with a congenital abnormality. In this context, it is important to develop national policies and strategies to prevent consanguineous marriages in Turkey.

Survey data on contraceptive use for about 80 countries are related to measures of contraceptive access, by method, from 1999 to 2009. Cross-tabulation and correlational methods are employed, with geographic comparisons and time trends. Total prevalence of use for five modern contraceptive methods correlates well to a variety of access measures. Greater access is also accompanied by a better balance among methods for both access and use. Sub-Saharan African countries show similar patterns though at lower levels. Improved access to multiple methods is consistently associated with higher levels of contraceptive use.

The hypothesis that family size limitation by parents enhances the upward mobility chances of their children in (post)industrial populations has a long-standing record in many disciplines, including sociology and economics, as well as evolutionary anthropology and social biology. Yet the empirical record supporting or contradicting the theory is surprisingly limited. The aim of this contribution is to develop a test of the effect of family size limitation on children’s intergenerational mobility. This test is applied to an urban population in Belgium that was in the process of experiencing its demographic transition, including the decline of fertility, at the end of the 19th century. The results indicate that the effect of family size was strong, even after controlling for parental social status as well as birth order. Surprisingly, the effects of birth order and family size appear to be largely independent.

An adapted ‘sense of coherence’ scale short form (SOC-13) was administered in nine languages of Eritrea with a total of 265 participants (162 women and 103 men) in order to assess ‘resilience’ in quantitative terms. Statistical analysis yielded significant differences in SOC scores between the displaced and non-displaced: mean=54·84 (SD=6·48) in internally displaced person (IDP) camps, compared with mean=48·94 (SD=11·99) in urban and rural settlements (t=3·831, p<0·001). Post-hoc tests revealed that the main difference is between IDP camp dwellers and urban (non-displaced) residents. Those in rural but traditionally mobile (pastoralist or transhumant) communities scored more or less the same as the urban non-displaced – i.e. significantly higher than those in IDP camps (p<0·05). Analysis of variance showed that displacement has a significantly negative effect on women compared with men (RR=0·262, p<0·001). Repeating the analysis for the three groups confirmed that urban and pastoralist/transhumant groups are similar, while women in IDP camps are lower scoring (RR=0·268, p<0·001), Hamboka women being worst affected due to their experience of serial displacement. These findings are interpreted and discussed in the light of qualitative information gleaned from the study participants’ interrogation of the content of the SOC scale; and in the wider context of historical, socio-political and cultural characteristics of Eritrea. The study’s implications for humanitarian and public health policy are considered.

The inability to have children affects couples worldwide and causes emotional and psychological distress in both men and women. Turkey is a country that lays particular emphasis on the issue of infertility, especially after experiencing a dramatic fertility decline over the last two decades. This study aimed to understand the changes in the prevalence of infertility in Turkey using three different approaches: the DHS Approach, the Constructed Approach and the Current Duration Approach. Furthermore, the factors contributing to elevated risks of infertility as derived from the Constructed Approach were investigated using four different logistic regression models. The data came from the 1993, 1998, 2003, 2008 and 2013 Demographic and Health Surveys conducted by the Hacettepe University Institute of Population Studies. The findings of the Constructed and Current Duration Approaches suggested that the prevalence of infertility decreased markedly from 1993 to 2013 in Turkey. This decline was the result of improvements in maternal health care services in Turkey, as well as an increase in the use of Assisted Reproductive Technology (ART), from 1.9% in 2008 to 4.1% in 2013. The results of the final logistic regression model suggested that the risk of infertility was significantly higher among women aged between 35 and 49 (p<0.01), uneducated women (p<0.01), women whose age at first marriage was over 30 (p<0.01), women defined as overweight (p<0.05) and women whose age at menarche was less than 12 years (p<0.05). This is the first nationwide study to examine the prevalence of infertility and its socio-demographic risk factors in Turkey, a developing country; previous studies have established these risk factors mainly in developed countries.