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.

Chlamydia trachomitis is the most common sexually transmitted infection in the UK and the number of cases diagnosed each year continues to rise. Although much is known about the risk factors for chlamydia from previous observational studies, less is known about how individuals put themselves at risk. Do they engage in just one risky type of behaviour or are certain individuals ‘risky’, engaging in multiple risky behaviours? This paper uses latent class analysis, applied to the National Survey of Sexual Attitudes and Lifestyles II (2000–2001), to determine whether a subgroup of high-risk individuals can be identified and explores which features of their behaviour distinguish them from other groups of lower risk individuals. A 3-class solution was obtained, splitting the sample on the basis of the number of sexual partners in the past year. Those with no sexual partners in the past year (8%) and one sexual partner in the past year (71%) were much less likely to have engaged in any of the other behaviours known to increase chlamydia risk. However, the group who had two or more sexual partners in the past year (21%) were much more likely to have also engaged in other risky behaviours. The number of partners in the past year is therefore a useful marker for identifying those at increased risk of chlamydia infection. Individuals under 25 years old, males and those who were single or previously married were more likely to be allocated to the risky group. However, in spite of observed higher incidence of chlamydia infection, individuals in the black ethnic minority groups did not show an increased prevalence of risky behaviour, after controlling for age, sex and marital status.

This paper examines contraceptive method use at different stages of the reproductive life course. Previous research on contraceptive practice in developed countries typically applies age as a proxy for reproductive history. While age is an essential and useful life course measure for understanding contraceptive use, investigations of contraceptive practice should also consider parity and fertility intentions, as they may be more accurate measures of reproductive life course stage. Analysis is based on data collected in the 2005 Household, Income and Labour Dynamics in Australia (HILDA) survey, a nationally representative sample of women of reproductive age (18–44). For women at risk of pregnancy, the most commonly used methods are easily reversed methods such as the oral contraceptive pill (30%) and condom (23%), medium-term methods such as the intrauterine device and implantation (5%) and permanent methods (7% tubal ligation and 9% vasectomy of partner). Logistic regression models are used to investigate the use of four popular contraceptive methods by parity, age and fertility intentions controlling for socio-demographic factors. The main findings indicate that the use of these methods varies substantially by the stage of a woman's reproductive life course: age, parity and fertility intentions are all associated with method use.

From March 2007 to March 2008 a cross-sectional study was conducted in Qatar to estimate the prevalence of consanguinity among Qataris and to assess their knowledge of the risks and their attitudes towards the practice. A secondary objective was to test the acceptability of sixteen Likert-style questions within the Qatari population. Face-to-face interviews using a 70-item structured questionnaire were conducted by three native Arabic-speaking medical students with 362 Qatari employees. Where consanguinity existed between the employee's parents, a diagram of the consanguinal relationship (phylogram) was completed. The response rate was 93%. By phylogram, 22% of participants reported a cousin relationship between their parents (consanguinal relationship) and another 15% reported that their parents were from the same tribe (affinal relationship). With respect to their own marital decision, 68% of the respondents had been married at least once. By phylogram, 35% of these reported a consanguineous relationship (first marriage), 9% reported only an affinal relationship and 56% reported that they were not married to a blood relative. Results on the sixteen Likert-style attitude questions were stratified by consanguinity status of parents and of self. In the stratification by consanguinity status of parents the top five attitudes differed by group but there appeared to be more similarity between the consanguinal and only tribal groups. Attitudinal results were stratified by sex. Results showed that the males had a stronger belief in several of the attitudes than females with the exception of causation of genetic abnormalities and health problems. The phylogram was shown to collect more detailed and explicit data than hard-coding. With respect to knowledge, the results showed that knowledge was imperfect with high proportions of participants not knowing that consanguinity has been implicated in autosomal recessive diseases such as thalassaemia, inborn errors of metabolism, deafness, anomalies of the extremities and specific congenital heart defects. Additionally, a sizeable proportion of the participants did not know that a more distant cousin marriage (e.g. third cousin) theoretically could be a less genetically risky choice to potential offspring than a closer cousin marriage (half-first cousin). These results indicate that more effort needs to be made in developing public health strategies to improve the population's understanding of the cost-benefit analysis involved in contracting consanguineous marriages given the goal of healthy offspring.

Scientists commonly use world average data on sex ratio at birth for India for want of dependable ones. Here an attempt is made to redress the problem to some extent. It is shown that this ratio has been high in India since the 1950s. The ratio has been strikingly high, even prior to the time of inception of prenatal sex identification technologies. The ratio shows a rising trend due to several biological reasons. In addition, it has been rising sharply for a couple of decades due to some socio-medical factors. The natural sex ratio at birth in India is noticeably higher than the world average.

Over the past century, the population of Korea has aged rapidly as a result of decreasing fertility and mortality. Furthermore, the percentage of the population aged 65 and older is expected to double from 7% to 14% within 18 years, a much shorter doubling period than in most other developed countries. As Korean society ages, interest in healthy and successful ageing has increased. However, although previous studies have examined various determinants of successful ageing, such as socioeconomic status, gender differences have been neglected. This study investigated gender differences as factors in successful ageing among elderly men and women. Successful ageing has been defined as having high levels of physical and social functioning. Physical functioning includes having no difficulties with activities of daily living (ADL) or instrumental activities of daily living (IADL). Social functioning is defined as participation in at least one of the following social activities: paid work, religious gatherings or volunteer service. Data for this study were obtained from a representative sample of 761 community-living individuals aged 65–84 years (340 males, 421 females); the respondents were interviewed face-to-face as part of the third wave of the Hallym Ageing Study (2007). Socioeconomic status appears to have a greater gender-specific effect on physical functioning than on social functioning. Especially for elderly men, a higher monthly individual income was significantly related to a higher level of physical functioning. Among elderly women, a higher level of education was associated with a higher level of physical functioning. In a major metropolis, elderly men had low social functioning and elderly women had low physical functioning. As Korea's population ages, successful ageing has received much attention. This study shows that policies promoting successful ageing must consider gender differences and associated socioeconomic factors.

The use of height data to measure living standards is now a well-established method in economics. However, there are still some populations, places and times for which the comparison across groups remains unclear. One example is 19th century Mexicans in the US. This study demonstrates that after comparing the statures of Mexicans born in Mexico and the US the primary source of the stature difference between the two groups was birth year, and the stature gap increased as the US economy developed while the Mexican economy stagnated. Moreover, the stature growth of Mexicans born in the US was related to vitamin D, and the Mexican relationship between stature and insolation was more like that of Europeans than Africans.

The mating pattern in a population determines the next generation gene pool and therefore its genetic structure. Besides socio-cultural and geographic factors, political barriers may influence the formation of couples. The present paper studies how the change of national border affected the mating pattern of Olivenza in Badajoz Province (Spain), which experienced a change of domain from Portugal to Spain in 1801. For the period analysed (1750–1850), 954 Catholic marriage records were transcribed. Data were sorted by decades in order to make a temporal study possible and analysed by means of diversity and repeated-pairs of surnames. Following the change of border the mating pattern modified. Coinciding with a larger number of mixed marriages with Spaniards, there was a progressive rise in the diversity of surnames. From 1811 to 1820 the analysis of repeated-pairs of surnames indicates the existence of preferential matings within Spanish and Portuguese lineages. After 1821 the above pattern became less clear due to the disappearance of the Spanish–Portuguese restrictions on choice of mate.