London School of Hygiene & Tropical Medicine

A study which provides the first ever comprehensive analysis of sexual behaviour around the world is published today in The Lancet, as part of a major series on sexual and reproductive health.

The paper¹ analyses data from 59 countries worldwide to answer questions such as when people start to have sex, how many sexual partners they have and whether they practise safer sex. The authors explore what the patterns and trends mean for sexual health and they review the literature on preventive approaches to improve sexual health status.

The paper contains a number of unexpected findings. In an age in which scare-stories about underage sex and promiscuity abound, there has in fact been no universal trend towards earlier sexual intercourse.

Another surprising finding is that it is the developed nations that report comparatively high rates of multiple partnerships, not those parts of the world which tend to have higher rates of HIV and AIDS, such as African countries. This has led the authors to suggest that social factors such as poverty, mobility and gender equality may be a stronger factor in sexual ill-health than promiscuity, and they call for public health interventions to take this into account.

Monogamy was found to be the dominant pattern in most regions of the world. Despite substantial regional variation in the prevalence of multiple partnerships, which is notably higher in industrialised countries, most people report having only one recent sexual partner. Worldwide, men report more multiple partnerships than women, but in some industrialised countries the proportions of men and women reporting multiple partnerships are more or less equal.

Trends towards earlier sexual experience were found to be less pronounced and less widespread than is sometimes supposed. In the majority of countries for which data were available, age at first intercourse had increased for women. In many developing countries, especially those in which first sex occurs predominantly within wedlock, the trend towards later onset of sexual activity among women has coincided with the trend towards later marriage, and this is particularly a feature of countries in Africa and south Asia.

The trend towards later marriage in most countries of the world has also led to an increase in premarital sex. However, most people are married, and married people have the most sex, with sexual activity among single people tending to be more sporadic, although it is greater in industrialised countries than in developing countries. Marriage does not always protect against sexual health risk. In Uganda, married women are the group for whom HIV transmission is increasing most rapidly, and a study in Kenya and Zambia showed that the sexual health benefits of marriage for women are offset by a higher frequency of sex, lower rates of condom use and their husbands' risky behaviours. In Asian countries, where early marriage is encouraged to protect young women's honour, early sexual experiences can be coercive and traumatic and, with respect to early pregnancy, dangerous for mother and child.

The researchers found that in a number of countries, rates of condom use at last sexual intercourse were increasing, in some cases, for example in Uganda, strikingly so. Rates of condom use are generally higher in industrialised than in non-industrialised countries, especially in women, and have continued to increase substantially in recent years.

Given the diversity of sexual behaviour revealed by the study, the authors call for a range of preventive strategies to be adopted to protect sexual health. They point out that in poor countries, sex is more likely to be tied to livelihoods, duty and survival, while in wealthier countries there is greater personal choice, even though power inequalities still persist.

The authors caution against the adoption of quick fixes and 'one size fits all' approaches to preventive interventions. They call for greater efforts to address the links between sexual behaviour and poverty, gender inequalities and social attitudes in efforts to improve sexual health status. Individuals need the facts and skills to make their behaviour safer, but changes to the social context are needed to support them in this.

Professor Kaye Wellings of the London School of Hygiene & Tropical Medicine, who led the team carrying out the study, comments: 'The huge regional diversity in sexual behaviour shows how strong social influences on behaviour are. No general approach to sexual health promotion will work everywhere, and no single component intervention will work anywhere. We need to know not only whether interventions work, but why and how they do so in particular social contexts'.

'The selection of public health messages needs to be guided by epidemiological evidence rather than by myths and moral stances. The greatest challenge to sexual health promotion in almost all countries comes from opposition from conservative forces to harm reduction strategies. Governments tend to shy away from supporting interventions other than those with orthodox approaches. Sexuality is an essential part of human nature and its expression needs to be affirmed rather than denied if public health messages are to be heeded'.

The findings will be launched at a press conference, held jointly with the Lancet, at Stewart House, 32 Russell Square, London WC1, from 10.00 am on Monday 30 October 2006.

¹ The paper is one of several which will appear in the Lancet over the course of the next few weeks. Other papers will focus on how unsafe sex contributes to rates of death and disability around the world, the pandemic of unsafe abortion and its implications for sexual and reproductive health, and the need for the both the international community and national governments to prioritise both sexual and reproductive health and family planning in order to achieve the Millennium Development Goals.

Notes:

Sexual behaviour is an important determinant of both fertility patterns and the transmission of sexually transmitted infections. Information about sexual behaviour is essential to inform preventive strategies and to correct myths about what constitutes safe and unsafe activity. Increased research in this area in the past two decades provides a historically unique opportunity to take stock of sexual behaviour, and efforts to safeguard it, at the beginning of the 21st Century.

Factors that determine variations and trends in sexual behaviour are environmental, and include shifts in poverty, education and employment; demographic trends such as the changing age structure of populations and the trend towards later marriage; increased migration between and within countries; globalisation of mass media; advances in contraception and access