Using the nationally representative sample of about 15,000 Add Health respondents in Wave III, the hypothesis is tested that masculinity–femininity in adolescence is correlated with sexual orientation 5 years later and 6 years later: that is, that for adolescent males in 1995 and again in 1996, more feminine males have a higher probability of self-identifying as homosexuals in 2001–02. It is predicted that for adolescent females in 1995 and 1996, more masculine females have a higher probability of self-identifying as homosexuals in 2001–02. Masculinity–femininity is measured by the classical method used by Terman & Miles. For both time periods, the hypothesis was strongly confirmed for males: the more feminine males had several times the probability of being attracted to same-sex partners, several times the probability of having same-sex partners, and several times the probability of self-identifying as homosexuals, compared with more masculine males. For females, no relationship was found at either time period between masculinity and sex of preference. The biological mechanism underlying homosexuality may be different for males and females.

This study examines the knowledge of sexually transmitted diseases (STDs) among male youths in Malaysia. A self-administered survey was carried out on a sample of 952 never-married males aged 15–24 years. The respondents were asked about their knowledge of STDs, how these diseases get transmitted and their sexual behaviours. The data showed that 92% of the respondents knew of at least one STD (syphilis, gonorrhoea, chlamydia, herpes, genital warts, yeast infection, trichomoniasis or HIV/AIDS). About 95% of them knew of at least one method of STD transmission. Urban and tertiary-educated male youths showed a substantially higher proportion of awareness of STDs and transmission methods compared with their rural and less-educated counterparts. The data also indicated that 10% of the study sample admitted to having had sexual experiences. There were still a large proportion of the respondents who were not aware of STDs other than syphilis and HIV/AIDS and the means of transmission, such as multiple sex partners, including those who claimed to be sexually active. Thus there is a need for more concerted efforts to disseminate information on STDs and transmission methods to a wider audience in Malaysia, especially youths in rural areas.

The role of religion in contraceptive use is an issue of significant debate. This study employed the 1990 and 2008 Nigeria Demographic and Health Survey data to examine differences and similarities in the influence of religious affiliation on non-use of modern contraceptives in Nigeria over the last two decades. The results suggest that a significant increase has occurred in the level of awareness of modern contraceptives in Nigeria over the last two decades, but that non-use remains very high. Religion could not independently predict non-use of modern contraceptives in 1990. Women of Islam and Traditional religions were more likely to have never used or not to be using modern contraceptives compared with Catholics and Protestants in 2008 (p<0.05). This can be explained by their poorer socioeconomic status relative to Catholics and Protestants. Therefore, improving women's socioeconomic status is an imperative in the promotion of modern contraception in Nigeria. Education and employment are critical in this regard and adherents of Islam and Traditional religions require special attention.

A sample of 35 South African Negro albinos and a normally pigmented matched control group have been studied for adjustment problems and attitudes towards this inherited condition. The results showed that although the albinos appeared to be as well adjusted as the controls, significantly more of the albino group had adjustment problems of a physical nature indicated by psychosomatic symptoms. Attitudes were found to be reasonably positive. One common local misconception was revealed: that albinos do not die but disappear or ‘vanish away’. There was very little understanding of the cause, mode of inheritance or the problems associated with albinism. It is concluded that relevant genetic counselling should be offered to the Negro albinos to enable them to understand their condition, its implications and the myths which surround it. Because albinism is so common in South Africa the education of the community in this connection is also desirable.

A time-dependent model of the probability of sexual intercourse, where the probability increases as the time from last intercourse increases, can produce waves in the expected frequency of sexual intercourse on the various dates of the menstrual cycle. These waves occur when the time-dependent model is linked with a period of abstinence, such as is usually found in most societies during the time of the menses. Previously, such waves have been attributed to cyclic hormonal changes in women without considering the full implication of a time-dependent model of sexual intercourse.

Understanding the social and cultural contextual determinants of sexual behaviour of adolescents and young adults is an essential step towards curtailing the spread of HIV. This study examined the effects of one cultural factor, ethnicity, on sexual abstinence, faithfulness, condom use at last sex, and risky sex among young people in Zimbabwe. Data from the cross-sectional, population-based 2005–06 Zimbabwe Demographic and Health Survey were used. Net of the effect of sociodemographic and social–cognitive factors, and using multinomial logistic regression, ethnicity was found to have a strong and consistent effect on sexual behaviour among youth. In addition, the study found that there were ethnic-specific and within-gender differences in sexual behaviour, for both men and women. Shona youth were more likely to be abstinent than Ndebele youth. Compared with Shona youth, Ndebele youth were more likely to have engaged in risky sex. However, Ndebele men were more likely have used condoms at last sex, compared with Shona men. For both men and women, sexual behaviour was more socially controlled. School attendance and religion exerted protective effects on sexual abstinence. For men only, those living in rural areas were less likely to be faithful and more likely to have engaged in risky sexual behaviour than those living in urban areas. The study attests to the fact that ethnic norms and ideologies of sexuality need to be identified and more thoroughly understood. In addition, the study provides evidence that in order to promote safe and healthy sexuality among young people in Zimbabwe, cultural, social and gender-specific approaches to the development of HIV prevention strategies should be seriously considered. Current success in the Abstinence, Being faithful and Condom use (ABC) approach could be strengthened by recognizing and responding to cultural forces that reproduce and perpetuate risky sexual behaviours.

This study applied a gender perspective to establish some of the anthropometric, body composition, health and socio-cultural determinants of active ageing. The variable ‘active ageing’ (presence/absence) was created based on cognitive and disability/illness/physical functioning, subjective health, satisfaction with life and productive activity performed, and used in predictive models to establish its relationship with anthropometric variables, physical health indicators and educational level. The sample consisted of 456 home-living individuals (169 men and 287 women; age range 54–75 years) from Madrid and Toledo in Spain. The women had a higher prevalence of obesity than the men (37.6% vs 29.0%), significantly greater fat accumulation in the abdominal area and worst perceived health (p=0.003). The frequency of active agers is higher in men than in women (38.4% vs 21.9%; p<0.001). Men and women were found to have distinctive ageing patterns. Health factors condition the presence of active ageing in women, while education factors are also relevant in men.

Bangladesh represents one of the few countries in south Asia where the pace of fertility decline has been unprecedented over the last three decades. Although there has been significant reduction in fertility levels at the national level, regional variations continue to persist, especially in Sylhet and Chittagong where the total fertility rates are well above the country average. Using data from three consecutive Bangladesh Demographic and Health Surveys (BDHSs) this paper assesses how fertility patterns in Sylhet and Chittagong differ from the rest of Bangladesh through a marriage cohort analysis of the parity progression ratios, and examines the factors determining the transition rates to higher parity in these two regions. Three cohorts of women are identified: those married during 1965–1974, 1975–84 and 1985–94. The results show that the probability that a woman from the recent cohort in Sylhet or Chittagong who had a third birth will have a fourth birth is nearly twice that of her counterpart in other regions. Social characteristics such as education, occupation, religion and residence have no effect on fertility in Sylhet and Chittagong. Additional period-specific analyses using the 2007 BDHS data show that women in Sylhet are considerably more likely to have a third or fourth birth sooner than those in other divisions, especially Khulna. The findings call for specific family planning policy interventions in Sylhet and Chittagong ensuring gender equity, promoting female education and delaying entry into marriage and childbearing.

This paper presents an analysis of trends in sexual activity by marital status and age, and their associations with contraceptive use. Understanding levels of, and trends in, sexual activity is important for assessing the needs for family planning services and for analysing commonly used family planning indicators. Data were taken from 220 Demographic and Health Surveys (DHSs) and 62 Multiple Indicator Cluster Surveys (MICSs) to provide insights into sexual activity by marital status and age in a total of 94 countries in different regions of the world. The results show the sensitivity of the indicator with respect to the definition of currently sexually active, based on the timing of last sexual intercourse (during the last 4 weeks, 3 months, or 1 year). Substantial diversity in sexual activity by marital status and age was demonstrated across countries. The proportion of married women reporting recent sexual activity (sexual intercourse during the last 4 weeks) ranged from 50% to 90%. The proportion of unmarried women reporting recent sexual activity did not exceed 50% in any of the 94 countries with available data, but showed substantial regional differences: it appeared to be rare in Asia and extremely varied within Africa, Europe and Latin America and the Caribbean. Among married women, sexual activity did not vary much by age group, while for unmarried women, there was an inverted U-pattern by age, with the youngest age group (15–19 years old) having the lowest proportion sexually active. The proportion of women who reported currently using contraception and reported not being sexually active varied by the contraceptive method used and was overall much greater among unmarried women. The evidence presented in this paper can be used to improve family planning policies and programmes to serve the diverse needs, for example regarding method choice and service provision, of unmarried women.

Humans exhibit sex differences in competitiveness, sensation seeking and risk-taking attitude, which are required in sports. These attributes are often linked to prenatal testosterone (PT) exposure. The second-to-fourth digit length ratio (2D:4D) is an indicator of PT exposure. A lower 2D:4D indicates higher PT exposure and vice versa. Males generally have a lower 2D:4D than females. Sensation- and/or thrill-seeking behaviours have also been found to be negatively associated with 2D:4D. Boxing and judo are considered to be high-risk sports. Voluntary participation in judo/boxing in contrast to aerobics can be guided by such behaviours and thus have an association with lower 2D:4D. This cross-sectional study included 167 female students from a military academy in Wrocław, Poland. Of them, 119 had voluntarily chosen aerobic exercise, and 48 opted for judo/boxing. Height, weight and second and fourth digit lengths were measured. Physical fitness was assessed using Eurofit tests. The two groups showed similar physical fitness and body size. However, the judo/boxing group had significantly lower mean 2D:4D values than the aerobics group. It is proposed that voluntary choice of participation in a sport discipline by women could be linked to the ‘organizational’ effect of intrauterine testosterone exposure during prenatal growth.

Research designs to study alcohol use and abuse have included twin, adoption and family history/high risk studies. Results have consistently implied a genetic factor in the aetiology of alcohol abuse. However, less research has been conducted in search of environmental factors. This study uses kinship structure in a large national dataset (the National Longitudinal Survey of Youth) to estimate (using DeFries–Fulker analysis) the extent of the shared genetic, non-shared genetic, shared environmental and non-shared environmental influences on alcohol use. The NLSY kinship sample contained 3890 pairs of cousins, half-siblings, full-siblings and twins between the ages of 14 and 21 in the initial year of the survey (1979). Estimates of heritability (h2) and shared environment (c2) were small to moderate for the entire dataset for both light drinking and heavy drinking behaviour, with h2 estimates slightly higher in each case. Non-shared genetic measures of self-esteem and locus of control accounted for a significant portion of the remaining variance in heavy drinking behaviour. Race and gender patterns showed c2 and h2 estimates that were also small to moderate for both light and heavy drinking behaviour. Significant non-shared effects were found for the White group for heavy drinking behaviour, and for male pairs for both heavy and light drinking behaviour. Additionally, implications and future directions are discussed.

The purpose of this study was to show the differences in the mortality rates of children from Catholic and Lutheran families in 19th century Poznań, and to elucidate the causes of these differences. Data from Catholic and Lutheran parish death registers were used. The infant death rate (IDR), neonatal and postneonatal death rates and life table biometric functions were calculated and causes of deaths were characterized. The worst child mortality values (IDR=394.4; neonatal and postneonatal death rates, respectively, 117.1 and 277.4; e0=16.14 years; Crow's Index=2.47) were obtained for the poor Catholic Parish of St Margaret. The lowest infant and neonatal and postneonatal death rates were observed to have occurred in the Catholic Parish of St Maria Magdalena situated in the city's more affluent central area (mortality rates, respectively, 269.9, 93.1 and 176.9; e0=24.63 years; Crow's Index=0.96). The widest range of differences with regard to death rates was found for the Lutheran Parish of St Cross (the infant, neonatal and postneonatal death rates were, respectively, 293.1, 99.1 and 193.9; e0=28.03 years; Crow's Index=0.92). The St Cross Parish encompassed a fairly large area of the city characterized by varying ecological conditions. Among infants and young children from the three studied populations a high frequency of deaths due to infectious diseases, diarrhoeas, dysenteries and tuberculosis were observed. Differences in the mortality of children from Catholic and Lutheran families in 19th century Poznań resulted from ecological conditions, among which water played the most important role, rather than from religious differences.

The basal body temperature was recorded by 1353 healthy fertile women aged 18 to 49 years inclusive through 12,247 cycles. The post-ovulatory (hyperthermic) phase of the cycle was significantly longer by 1·31 days in cycles with a slow or staircase rise of temperature than in cycles with an acute rise. The hyperthermic phase increased in length in a rectilinear fashion from 10 to 13 days as the total cycle length rose from 22 to 29 days; over total cycle lengths from 29 to 33 days the length of the hyperthermic phase remained around 13 days.

The Standard Progressive Matrices test was standardized in Estonia on a representative sample of 4874 schoolchildren aged from 7 to 19 years. When the IQ of Estonian children was expressed in relation to British and Icelandic norms, both demonstrated a similar sigmoid relationship. The youngest Estonian group scored higher than the British and Icelandic norms: after first grade, the score fell below 100 and remained lower until age 12, and after that age it increased above the mean level of these two comparison countries. The difference between the junior school children and the secondary school children may be due to schooling, sampling error or different trajectories of intellectual maturation in different populations. Systematic differences in the growth pattern suggest that the development of intellectual capacities proceeds at different rates and the maturation process can take longer in some populations than in others.

This study examines the delay between first marriage and first live birth in China among a sample of women who married between 1980 and 1992. Most couples in China only use contraception after the first child is born. Most sample women had their first child within 2 years of marriage. However, there are significant rural–urban differences in the first birth interval, indicating that there was most probably deliberate fertility regulation after marriage among many urban couples. Survival analysis shows that place of residence, level of education, age at first marriage and marriage cohort affect the first birth interval.

The associations between cigarette smoking before and during pregnancy and maternal body size (pre-pregnancy weight status, end of pregnancy weight status, weight gain during pregnancy) and newborn size (birth weight, length, head circumference, arcomial circumference), as well as birth modus, were tested in 7803 single full-term births in Vienna. Nicotine consumption before and during pregnancy was found to be associated with smaller and lighter newborns, although maternal weight status and weight gain during pregnancy was signi.cantly higher in smokers. Furthermore, a higher incidence of Caesarean sections was found in smokers. A reduction in the number of daily smoked cigarettes was associated with a lower percentage of low weight newborns (<2500 g).

Child marriage has significant negative impacts, not only for girls, but also for a range of development outcomes. This study aimed to assess, in a more detailed way than done so far, the magnitude of the relationship between child marriage and total fertility in multiple countries representing diverse settings. Data from the most recent Demographic and Health Surveys in the fifteen countries of interest were used. Analysis was restricted to a subsample of women aged 35–49 years in order to capture completed fertility. Poisson regression was conducted to estimate the impact of each additional year of early marriage on the total number of births women have, controlling for selected sociodemographic characteristics. Counterfactual analyses were carried out to estimate the reduction in the number of children that women would have over their lifetime in the absence of child marriage. Controlling for socioeconomic and other characteristics, girls who marry as children have more children over their lifetime than women marrying after the age of 18. Nationally, across fifteen countries, the reduction in total fertility from ending child marriage ranges from 0.24 to 1.06 children per woman. The simulated change in total fertility that would result from ending child marriage tends to be higher in countries that have a higher incidence of child marriage.

The hypothesis that the month-specific rate of return to ovarian cyclicity after childbirth is causally related to suckling pattern was tested for a population of New Mexican women recruited within the service area of New Mexico Highlands University and for a nationwide USA subpopulation of women recruited through membership of the Couple to Couple League (CCL). Survival analysis for time-dependent covariates was used, and significant predictors of the first postpartum menses were found. Important differences were detected in the suckling pattern for the two groups and a 5:2 differential was found in their respective rates of menstrual cycle recovery. Although the two groups were comparable perinatally, daily and time-windowed breast-feeding performance fell off at twice the rate for the New Mexico population when contrasted with the CCL sample. For both populations, the introduction of solid feeds was a strong and significant predictor of returning menstrual cyclicity, independent of suckling pattern.

A cross-sectional study was performed on 1527 Thai women, 1270 of whom had received from one to twenty-five consecutive 3-month contraceptive injections of 150 mg of depo medroxyprogesterone acetate (DMPA) and a monthly oral oestrogen supplement. Analysis of data revealed that use of DMPA and breast nodules are independent.

Consanguineous marriage is preferred in many countries, especially by Muslims. Despite the increasing education rate in Saudi Arabia, the prevalence of consanguineous marriage does not seem to be decreasing as quickly as expected. The present study aimed to investigate the current prevalence of consanguineous marriage among educated married adults in Riyadh and to determine the factors favouring it. The cross-sectional study was conducted in 2017–18 using an online questionnaire. A total of 550 questionnaires were sent to married adults of both sexes and 417 responded, giving a response rate of 75.8%. The questionnaire consisted of two parts: the first section asked for demographic data such as age, sex, educational level, residential area and family size. The second part was about consanguineous marriage and its degree if present, family history of consanguineous marriage and level of awareness of its potential negative impact on offspring. It was found that the prevalence of consanguineous marriage among the participating educated adults was 39.8% and most of these were married to a first cousin. Neither level of education nor age affected the likelihood of consanguineous marriage, but predictors for the practice among the educated participating adults were having a family history of consanguineous marriage, having consanguineous parents and having a personal preference for consanguineous marriage. In conclusion, the prevalence of consanguineous marriage among educated adults in Riyadh was still high in 2018, especially among first-cousin relatives, and this was related to family history and personal preference rather than educational level or age. It is recommended that further research is conducted to assess the level of knowledge about, and attitude towards, consanguineous marriage among adults in Saudi Arabia.