In sickness and in health: Same-sex marriage laws and sexually transmitted infections

► This paper analyzes the relationship between same-sex marriage laws and sexually transmitted infections in the United States. ► Laws banning same-sex marriage are unrelated to gonorrhea rates, a proxy for risky heterosexual behavior. ► There may be a modest positive association between same-sex marriage bans and syphilis, a proxy for risky homosexual behavior. ► Laws permitting same-sex marriage are unrelated to either gonorrhea or syphilis. ► Evidence suggests that same-sex marriage laws reflect social attitudes toward gays.