Two Emory economists have found that a constitutional ban on gay marriage increases the rate of HIV by four per 100,000 people. This the first study of the impact of social tolerance levels toward gays in the United States on the HIV transmission rate.

The economists cite the passage of bans on gay marriage, such as the recent passage and upholding of Proposition 8 in California, as causing more underground sexual behavior due to an increase in intolerance to homosexuality.

“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.

Andrew Francis, also an assistant professor of economics, said that policymakers will consider the two men’s research when ruling on gay marriage.

For more information, read the full Science Daily article here.