Data from the US National Surveys of Family Growth appears to show that American gay men have become less promiscuous over the decade that same-sex marriages first began to become available to them.

Researchers compared data from gay men aged between 15 and 44 who took part in the National Surveys of Family Growth in 2002 to those who took part between 2006 and 2010 and found a statistically meaningful drop in the numbers of sexual partners they reported having in the last year.

Between 2002 and 2010 the average number of sexual partners dropped from 2.9 to 2.3 overall and fell from 2.9 to 2.1 among gay men under 24.

The drop in the number of sexual partners was found to be greater in gay men living in suburbia, while the number of sexual partners living in city centers remained the same between 2002 and 2010.

Condom use also remained unchanged between 2002 and 2010 with 57 percent of respondents saying they had not used a condom in their last sexual encounter in 2002 compared to 58 percent in 2010. Only 41 percent of respondents had had a HIV test in the past years in both surveys however the number of gay men who had never been tested for HIV dropped from 25 percent to 15 percent.

Commenting on the results, the researchers wrote that ‘gay men appear to have taken steps that could reduce their HIV risk by using a method that has received little emphasis in HIV prevention programmes for gay men – reducing their number of partners – while not increasing condom use, which has received the most emphasis.’

The study also found a drop in the number of gay men having sex in exchange for drugs or money with 15 percent reporting having some form of paid sex in 2002 and just 3 percent in 2010, and also a drop in the number of gay men having sex either on an injected drug or with someone who had injected a drug with the numbers there dropping from 12 to 5 percent.

Researchers also noted a decline in the number of men who have sex with men who also have sex with women with 38 percent of those who took part in the 2002 study saying they engaged in sex with both genders compared to just 25 percent in 2010.

One year after the first study was conducted, the state of Massachusetts became the first US state to legalize same-sex marriage. Since then a further nine states and the District of Columbia have legalized same-sex marriage with Rhode Island becoming the most recent to do so.