The second paper in the Lancet Online/Series presents the results of the first global analysis of sexual behaviour data.
Kaye Wellings (London School of Hygiene & Tropical Medicine) and colleagues analysed data from 59 countries worldwide, which included information on age at first sexual experience, condom use, and number of sexual partners.
They found that contrary to popular beliefs, there has in fact been no universal trend towards earlier sexual intercourse. Almost everywhere, sexual activity begins for most men and women in the later teenage years (ages 15–19 years), with earlier onset for men and later for women.
Monogamy is the dominant pattern in most regions of the world. Despite substantial regional variation in the prevalence of multiple partnerships most people report having only one recent sexual partner.
Surprisingly, the study found that it is developed nations that report comparatively high rates of multiple partnerships, not those parts of the world which tend to have higher rates of sexually transmitted infections and HIV, such as African countries. This suggests that social factors such as poverty, mobility and gender equality may be a stronger factor in sexual ill-health than promiscuity.
Married people have the most sex but a trend towards later marriage in most countries has led to an increase in the prevalence of premarital sex. The analysis found that sexual activity among young single people tends to be sporadic, but is more common in industrialised countries than in developing countries, and is more likely to be unprotected than among older unmarried people. As a result, adolescents have high rates of unintended pregnancy, unsafe abortions, and STIs.
In some developing countries, rates of condom use at last sexual intercourse are increasing; in the case of Uganda, strikingly so. Overall, however, rates of condom use are predictably lower in non-industrialised countries. This is likely to be due to the poor access and provision of sexual health services, say the authors.
Professor Wellings concludes: "Men and women have sex for different reasons and in different ways in different settings. This diversity needs to be respected in a range of approaches tailored to whole societies, and to particular groups and individuals within them…The comparative data are important in countering misinformation and quelling fears relating to sexual behaviour. The selection of public-health messages needs to be guided by epidemiological evidence rather than by myths and moral stances."
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