Study Finds Marriage Equality Doesn’t Affect Opposite-Sex Marriage Rates

States that have passed marriage equality legislation have seen no impact on their rates of opposite-sex marriage, according to a new study published Tuesday.

The study, authored by Alexis Dinno and Chelsea Whitney of Portland State University’s School of Community Health, was published in the online research journal PLOS ONE. Dinno and Whitney compared rates in the 13 states which had legalized marriage equality or strong civil unions before 2009 to those in other states, finding that opposite-sex marriage rates did not differ in those states to a statistically significant degree:

“We found that state rates of opposite sex marriage in the U.S. from 1989–2009 do not significantly differ when same sex marriage and union laws are in force compared to when they are not in force, contrary both to concerns raised by opponents of same sex marriage and same sex civil unions,” the authors wrote.

The idea of marriage equality as an “attack on traditional marriage” is a favored talking point of opponents. In April, former Republican presidential candidate Rick Santorum said legalizing same-sex marriage would discourage marriage among heterosexual couples because the traditional understanding of marriage as a means of reproduction would erode. The Family Research Council has argued that “traditional” marriage keeps men from cheating on their wives once the women are no longer fertile. Two anti-marriage equality advocates from the Heritage Foundation said it would lead to the erosion of marital norms, even though opposite-sex couples already cheat, divorce, and decline to have children (or are unable to), even in states that still restrict marriage.


While there is no harm to opposite-sex couples, studies have shown that ballot initiatives banning same-sex marriage are actually psychologically harmful to the gay community.

Last month, Delaware and Minnesota became the 11th and 12th states to legalize full marriage equality for same-sex couples. During final arguments for the Delaware legislation, state Sen. Karen Peterson came out publicly and offered a stinging rebuke to proponents of the argument: “If my happiness somehow demeans or diminishes your marriage, you need to work on your marriage,” Peterson said.