This study analyzes the factors that have facilitated or hindered liberalization of abortion and same-sex marriage in Argentina and Mexico. In particular, this project will examine the argument that differences in mobilization strategies, available resources, contrasts in framing and patterns of alliances in the political system have played fundamental roles in shaping divergent policy outcomes on these controversial social issues. Against the backdrop of democratization, changes in institutional configurations, and the rising acceptance of sexuality in the context of universal human rights, these policy issues are subject to the contingencies of contentious politics. The argument is twofold: First, international norm diffusion through transnational advocacy networks has had an important impact on the domestic transformation of gender policies (Finnemore and Sikkink, 1998; Keck and Sikkink, 1998; Risse and Sikkink, 1999; Risse and Ropp, 1999; Petchesky, 2003; Kollman, 2009). Second, simultaneous domestic mobilizations, which may claim legitimacy from international norms, are constrained by domestic institutions and the legal environment and their strategies for navigating these constraints may yield liberalization if effective alliances are forged to take advantage of open or moderately open political opportunity structures. In short, the argument departs from the premise that "social movements, organizations, and legal systems are clearly interdependent in a myriad of ways" (Edelman, Leachman and McAdam, 2010: 668). Based upon this perspective, this study is situated within the growing literature of policymaking analysis of LGBT rights and women's rights. Indeed, this study finds that the articulation of domestic and international contention has created new avenues for demands that were previously unthinkable. Argentina and Mexico show that because of globalization domestic structures are more porous and prone to claims through collective action. In addition, there is a "growing connection between internal contention and international conflict" (Tarrow, 2005: 212) that leads to the necessity of looking at the processes and the mechanisms by which transnational activists are able to act domestically.