Many people argue that allowing same-sex couples to marry reduces the value of marriage to opposite-sex couples.  This paper examines how the recent changes in legal recognition laws designed to include same-sex couples have altered marriage rates.

Using a difference-in-differences strategy that compares how marriage rates change after legal recognition in states that alter legal recognition versus states that do not, this paper finds no evidence that allowing same-sex couples to marry reduces the opposite-sex marriage rate.  Although the opposite-sex marriage rate is unaffected by same-sex couples marrying, it does decrease when domestic partnerships are available to opposite-sex couples.