Though it's unlikely to cause a hubbub remotely equivalent to the stir of Alfred Kinsey's 1948 book Sexual Behavior in the Human Male, the first worldwide study of sexual behavior appears online this week in the British medical journal The Lancet. Rather than exposing societal taboos occurring everywhere, the report sheds light on the effect of global efforts to curb risky practices. The team of researchers, led by Kaye Wellings, a professor of sexual health at the London School of Hygiene and Tropical Medicine, analyzed nearly 200 studies on demographic sexual behavior in 59 countries published between 1996 and 2006 to obtain their results on the state of international sexual health.

Some of the primary findings of this meta-analysis are unsurprising: Monogamy is the dominant sexual pattern globally. Married individuals--which constitute most people studied--have the most sex. Men report having engaged in sex with more partners than women in a given year. Instances of males with multiple partners, however, were more frequent in industrialized nations, Wellings says, than in places such as Africa, where sexual health education is relatively unsophisticated. "We certainly expected to see that in African countries there would be an equal prevalence of multiple partnerships," she says. "I don't think we expected to see less reporting of them."

That is just one of many surprises found in the meta-analysis. Contrary to popular belief, there is no evidence that young people are engaging in sexual intercourse at earlier ages--the first instance of sexual activity for both genders generally occurs at between 15 and 19 years of age globally. "There's always a tendency to think that things are going to 'hell in a handbasket,'" remarks Richard Parker, the sociomedical sciences department chair at Columbia University's Mailman School of Public Health. "A lot of what we say we think about trends in sexual behavior are basically kind of knee-jerk, impressionistic conclusions that we make, rather than because we looked at the data." Another surprising finding is that married women are actually at greater risk of unhealthy sexual behavior-they find it harder than single women do to convince their partners to use condoms.

One optimistic finding is that condom use is up worldwide. From 1993 to 2001, in 19 African countries, the rate of condoms employed to prevent pregnancy increased from five to 19 percent of the time; at the last instance of intercourse, the increase was from 19 percent to 28 percent. Wellings explains, however, that "there are parts of this that are reassuring and parts that are not: If you look at the [cross-national] data on condom use, you then see a big difference between the richer and poorer countries." Although numbers have improved in less developed parts of the world, condom use still lags far behind industrialized nations. "The protection of risk behavior is less prevalent in the poorer countries," she says.

Going forward, the authors advocate targeting "broader determinants of sexual health," urging public health organizations to focus on elements such as gender inequality, class and existing social networks. They cite programs like the 100 percent condom-use initiative in Thailand's commercial sex sector and Uganda's national AIDS effort-the first of its kind in Africa. The latter, rather than attacking HIV/AIDS in a quick and general sense, began with getting the message to high risk individuals before passing it on to the rest of the country.

Vague, general messages not specifically targeted at any group "have been ineffective almost everywhere," points out Columbia's Parker. "I think that's been a lesson that we've learned not only from the data in a meta-analysis like this, but from 20 years, now 25 years of HIV prevention work around the world."