- RAND researchers reviewed 96 studies conducted over 20 years on the effects of granting same-sex couples access to legal marriage. The review found no reliable evidence of adverse consequences to the general U.S. population.
- On the contrary, the researchers found some evidence of an increase in marriage resulting from legalization of marriage between same-sex partners. This increase was not driven solely by newly marrying same-sex couples.
- The analyses found no evidence of a statistically significant increase in nonmarital cohabitation (living together while unmarried) by different-sex couples after states legalized marriage for same-sex couples.
- The researchers found no consistent changes in divorce as a consequence of legalizing marriage for same-sex couples.
- Finally, the researchers found no consistent evidence of a negative shift in young adults' attitudes toward the institution of marriage—and some evidence of an improvement—after states legalized marriage for same-sex couples.
The researchers' analyses suggest that the arguments available to opponents of legal marriage for same-sex couples today are narrower than they once were. Where once it was possible to speculate about the consequences of extending legal status to same-sex couples in the United States, now the consequences are known. There is no empirical basis for concerns that allowing same-sex couples to marry will negatively affect the intentions and choices of different-sex couples and families. The only empirical evidence of effects that the researchers found suggests that policies allowing marriage for same-sex couples lead to a renewed salience of marriage among the broader public.