Why is gender such an unreliable predictor of support for policies that promote gender equality? Women and men alike are generally raised in households and local contexts where men play an outsized role in shaping norms and wield a disproportionate amount of physical, economic, and social power, influencing the development of attitudes toward gendered policies. Across two national surveys, we look at the influence of various local institutions on attitudes toward gendered policies and find that family norms play a uniquely important role. In a follow-up survey experiment conducted on a national probability sample of American teenagers, we show that thinking of a single family member with liberal or conservative attitudes towards gender can shape teenage support for gender-related policies, particularly among boys. Together our findings highlight the powerful role that a single family member can play in shaping public opinion on gender equality.