News Release: Faculty Experts, Research

Jun. 4,  2009

Study Links Gay Marriage Bans to Rise in HIV Rate

News Article ImageHugo Mialon, left, and Andrew Francis are applying economic theories to calculate how social attitudes and policies affect HIV transmission.

Bans on same-sex marriage can be tied to a rise in the rate of HIV infection, a new study by two Emory economists has found.

In the first study of the impact of social tolerance levels toward gays in the United States on the HIV transmission rate, the researchers estimated that a constitutional ban on gay marriage raises the rate by four cases per 100,000 people.

"We found the effects of tolerance for gays on HIV to be statistically significant and robust – they hold up under a range of empirical models," says Hugo Mialon, an assistant professor of economics.

"Laws on gay marriage are in flux and under debate," added Andrew Francis, also an assistant professor of economics, citing the recent decision by the California Supreme Court to uphold a ban on same-sex marriage. "It's a hot issue, and we are hoping that policymakers will take our findings into account."

The study used data from the General Social Survey (GSS), which has tracked the attitudes of Americans during the past four decades. The economists calculated that a rise in tolerance from the 1970s to the 1990s reduced HIV cases by one per 100,000 people, and that laws against same-sex marriage boosted cases by 4 per 100,000.

"Intolerance is deadly," Mialon said. "Bans on gay marriage codify intolerance, causing more gay people to shift to underground sexual behaviors that carry more risk."

Outstanding law and economics paper of the year

Francis and Mialon previously did an analysis of the optimal penalty for sexually transmitting HIV. Published in March of 2008, the study was recently named outstanding paper of the year by the editors of the American Law and Economics Review.

The two researchers developed a game theory model for sexual behavior, which demonstrated that laws in some states regarding the sexual transmission of HIV are generally inefficient at slowing the spread of the disease.

In Georgia, for instance, failing to inform a partner that you are HIV positive prior to having sex is a felony punishable by up to 30 years in prison. The same penalty can apply even if the person who is HIV positive uses precautions such as a condom during sex, and even if the sexual partner does not contract HIV. The law does not apply, however, to people who do not know that they are HIV positive and transmit the virus.

For more breaking news from the natural and social sciences at Emory, visit


News Release Tools