This is interesting:
“In a new study conducted by economists at Emory University, it has been found that banning same-sex marriage raises the U.S. HIV infection rate by four cases per 100,000 people. Using data from the General Social Survey, a popular research tool that has gauged American public opinion for over four decades, Hugo Mialon and co-researcher Andrew Francis found that a widespread increase in tolerance for homosexuality between the 1970s and the 1990s resulted in a decrease of one HIV infection per 100,000 people. Recent controversy over the issue of same-sex marriage has led to a new culture of intolerance say the researchers, which, in turn, leads to riskier sexual behavior.
“’Intolerance is deadly,’ said Mialon, assistant professor of economics at Emory. ‘Bans on gay marriage codify intolerance, causing more gay people to shift to underground sexual behaviors that carry more risk.’ Mialon continues, ‘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.’ Francis adds, ‘Laws on gay marriage are in flux and under debate. It’s a hot issue, and we are hoping that policymakers will take our findings into account.'”
The article also links to the study itself; those interested and with the capacity to do so can read the whole (40+ page) thing and draw their own conclusions about methodology, inference, and conclusion. But at least intuitively, this is a plausible connection. A society that shames behaviors and drives them underground can’t claim surprise when unhealthy outcomes result.