My research examines the adoption and diffusion of marriage equality policies in states across the US. I analyze how gender equality and reproductive technology reshape norms around marriage and family to foster the broad support of same sex marriage policies. Scholars recognize that the institution of marriage is modernizing, but little research exists on how these changes have influenced the public policies that are in place to regulate this union. I use data from a variety of government sources to measure inequality between the sexes in economic, political, and social domains, as well as the prevalence of assistive reproductive technology. An event history analysis is employed to analyze whether these factors are important to a state’s decision to adopt, after controlling for other influential variables. The results of my analysis indicate that gender equality is not a significant factor in decisions to adopt, but the assistive reproductive technology does have a significant and robust impact on policy adoption. The significance of assistive reproductive technology to the adoption of same sex marriage policies demonstrates that changing norms and growing possibilities around childbearing cultivate support for public policies that institutionalize these shifts. The findings from my study are important and useful, as same sex marriage policies have far-reaching implications. This line of inquiry highlights how changing social norms are powerful enough to prompt the adoption of public policies that more accurately depict the values and beliefs of a modern society.