While the gender gap in political behaviour has been extensively studied, the mechanisms that lead women to perceive politics as a male-dominated sphere, and to show less interest, or confidence, remain underexplored. Specifically, the gap in internal political efficacy persists significantly across European countries, with women consistently feeling less capable of participating in politics than men, even after controlling for socioeconomic characteristics. Traditional explanations for the gender gap are built on three pillars: unequal resource distribution, the underrepresentation of women in politics, and psychological factors that alienate women from the political realm. This research contributes to the literature by integrating insights from these grand theories and examining the moment the gap begins to emerge: when girls and boys develop their political attitudes. Unequal resource benefits theory suggests that after gaining access to education and work, men and women benefit differently from these resources. Psychological perspectives, particularly gendered political socialization, argue that women are socialized to view politics as male-dominated. This study investigates whether, given the same family structure, measured by parents' educational level and occupational status, the development of political efficacy differs for boys and girls over the lifecycle. Using 10 years of panel data with household structure from the British Household Panel, the preliminary analysis reveals that while both boys and girls benefit from higher parental resources, girls experience significantly smaller gains. By framing these findings within lifecycle and socialization dynamics, this paper sheds light on how structural and psychological factors intersect to sustain gendered patterns of political behaviour