When Pope Benedict XVI commented this month that condom distribution isn’t helping, and may be worsening, the spread of HIV/AIDS in Africa, he set off a firestorm of protest. Most non-Catholic commentary has been highly critical of the pope. A cartoon in the Philadelphia Inquirer, reprinted in the Washington Post, showed the pope somewhat ghoulishly praising a throng of sick and dying Africans: “Blessed are the sick, for they have not used condoms.”

Yet, in truth, current empirical evidence supports him.

We liberals who work in the fields of global HIV/AIDS and family planning take terrible professional risks if we side with the pope on a divisive topic such as this. The condom has become a symbol of freedom and — along with contraception — female emancipation, so those who question condom orthodoxy are accused of being against these causes. My comments are only about the question of condoms working to stem the spread of AIDS in Africa’s generalized epidemics — nowhere else.

In 2003, Norman Hearst and Sanny Chen of the University of California conducted a condom-effectiveness study for the United Nations’ AIDS program and found no evidence of condoms working as a primary in HIV-prevention measures in Africa. The U.N. agency quietly disowned the study. (The authors eventually managed to publish their findings in the quarterly Studies in Family Planning.) Since then, major articles in other peer-reviewed journals such as the Lancet, Science, and BMJ have confirmed that condoms have not worked as an intervention in the population-wide epidemics of Africa. In a 2008 article in Science called “Reassessing HIV Prevention” 10 AIDS experts concluded that “consistent condom use has not reached a sufficiently high level, even after many years of widespread and often aggressive promotion, to produce a measurable slowing of new infections in the generalized epidemics of sub-Saharan Africa.”

Let me quickly add that condom promotion has worked in countries such as Thailand and Cambodia, where most HIV is transmitted through commercial sex and where it has been possible to enforce a 100 percent condom-use policy in brothels (but not outside of them). In theory, condom promotions ought to work everywhere. And intuitively, some condom use ought to be better than no use. But that’s not what the research in Africa shows.

Why not?

One reason is “risk compensation.” That is, when people think they’re made safe by using condoms at least some of the time, they actually engage in riskier sex.

Another factor is that people seldom use condoms in steady relationships because doing so would imply a lack of trust. (And if condom-use rates go up, it’s possible we are seeing an increase of casual or commercial sex.) However, it’s those ongoing relationships that drive Africa’s worst epidemics. In these, most HIV infections are found in general populations, not in high-risk groups such as sex workers, gay men, or persons who inject drugs. And in significant proportions of African populations, people have two or more regular sex partners who overlap in time.

A study in Malawi showed that even though the average number of sexual partners was only slightly over two, fully two-thirds of this population was interconnected through such networks of overlapping, ongoing relationships.

So what has worked in Africa? Strategies that break up these multiple and concurrent sexual networks — or faithful mutual monogamy or at least reduction in numbers of partners, especially concurrent ones.

In Uganda’s early, largely home-grown AIDS program, the focus was on “Sticking to One Partner” or “Zero Grazing” (which meant remaining faithful within a polygamous marriage) and “Loving Faithfully.” These simple messages worked. More recently, the two countries with the highest HIV-infection rates, Swaziland and Botswana, have both launched campaigns that discourage people from having numerous and concurrent partners.

Don’t misunderstand me; I am not anti-condom. All people should have full access to condoms, and condoms should always be a backup strategy for those who will not or cannot remain in a mutually faithful relationship. Moreover, liberals and conservatives agree that condoms cannot address challenges that remain critical in Africa such as cross-generational sex, gender equality, and an end to domestic violence, rape, and sexual coercion.

Surely it’s time to start providing more evidence-based AIDS prevention in Africa.