While a substantial literature documents that men who feel threatened by social change, gender equality, and women's rising aspirations tend to support far-right parties, there is limited evidence on the role of early socialization in shaping such attitudes. Bridging theories of cultural backlash and the demand-side dynamics of far-right support with theories of political socialization, we argue that early exposure to a female authority figure—specifically, an older sister—durably impacts men’s outlook on traditional gender roles by confronting them with female agency and authority early in their lives. This experience should reduce their susceptibility to the culturally conservative ideologies advanced by far-right parties, which emphasize traditional gender hierarchies and the marginalization of women in power. To test this proposition, we draw on a unique survey dataset linked to Swedish registry data that connects respondents' party preferences with detailed information on their family background, allowing us to exploit the random assignment of growing up with an older sister. Our findings show that men exposed to a female authority figure in early life are significantly less likely to vote for the far right. This large effect remains robust after accounting for a range of confounding factors, including socio-economic status, parental education, and family structure. In drawing attention to the role of early childhood socialization in influencing voters' support for the far right, our study enhances our understanding not only of the micro-level foundations of far-right support, but also of the critical role of internalized social norms in shaping political behavior.