By EJ Mundell
MONDAY, Oct. 6, 2014 (HealthDay News) -- When gays and lesbians have access to government-sanctioned marriage, or engage in highly committed "marriage-like" unions, their rates of break-up are the same as those of heterosexuals, a new study finds.
The study was released Monday, coinciding with an announcement from the U.S. Supreme Court that it would refuse to hear cases from five states seeking to maintain bans on same-sex marriage. Experts believe that this decision raises the odds that same-sex marriages will be recognized in those states.
The data used in the study covers 2009 through 2012, before the Supreme Court decision overturning the Defense of Marriage Act (DOMA). That decision helped encourage many more states to support same-sex marriage.
However, even the earlier data used in the current study suggests that "same-sex couples and heterosexual couples have statistically indistinguishable rates of [marriage] breakup," according to the study's author, Michael Rosenfeld, associate professor of sociology at Stanford University.
The study appears in the October issue of the Journal of Marriage and Family.
Rosenfeld noted that prior research suggested that same-sex relationships might not be as stable over the long term as straight couples. However, none of those studies had access to the nationally representative data of his new report.
In the new study, information was collected through successive surveys about How Couples Meet and Stay Together. Beginning in 2009, these polls tracked the relationships of about 3,000 American couples and followed them year by year through 2012.
Nearly 500 of the pairings in the surveys were same-sex couples.
Of course, between 2009 and 2012 many states did not sanction same-sex marriages. For that reason, Rosenfeld also included "marriage-like" unions such as domestic partnerships, civil unions, and other arrangements "that include a strong interpersonal commitment" from each partner, he said.
He found that -- for couples in either a marriage or a marriage-like union -- the annual break-up rate for either straight or gay couples was below 3 percent. Additionally, there wasn't a significant difference in the annual break-up rate for gay male couples or lesbian couples.
Based on the study data, "married couples [either straight or gay] are dramatically more likely to stay together than unmarried couples at all levels of relationship quality and at all relationship durations," Rosenfeld wrote.
And, legislation did seem to encourage marriage or marriage-like unions among gay or lesbian couples, he added. For example, in the survey conducted in 2009, "the percentage of same-sex couples who were married was 42 percent in states that recognized same-sex couples (in any way) compared to a 28 percent rate of marriage for same-sex couples who lived in states that did not recognize formal unions for same-sex couples," Rosenfeld wrote.
In the end, the study suggests that, "across all types of couples, couple stability appears to be primarily a function of the couple's own history, their relationship longevity, and their marital commitment," Rosenfeld said.