Researchers at Columbia University say the number of visits by gay men to health clinics in Massachusetts dropped significantly after same-sex unions were legalized in that state.
The researchers surveyed the demand for medical and mental healthcare from more than 1,200 gay men registered with a Massachusetts health clinic in the 12 months prior to the 2003 change and the 12 months afterwards and found a 13-percent drop in healthcare visits after the law was enacted.
This was regardless of whether the men were in a stable relationship, the American Journal of Public Health reported.
There was a reduction in blood pressure problems, depression and "adjustment disorders," which could be the result of reduced stress, researchers said.
"Our results suggest that removing these barriers improves the health of gay and bisexual men," study leader Mark Hatzenbuehler said.
"There is a known link between health and happiness," a spokesman for the Terrence Higgins Trust, a sexual health and HIV charity in the United Kingdom, told the BBC.
"Marriage equality may produce broad public health benefits by reducing the occurrence of stress-related health conditions," the spokesman said.