Gender norms about parental labor supply are central to explaining persistent gender inequalities in the labor market, yet their causal determinants remain poorly understood. We examine whether people’s gender attitudes are driven by mothers’ and fathers’ earnings, which may shape views about the efficient allocation of paid work and care. In a large-scale representative vignette experiment in Germany (N > 10,000), we randomly vary pre-childbirth earnings and measure whether respondents recommend that the mother (father) stay home with the child while the father (mother) works full-time. Without specifying earnings, 90% recommend that the mother stay home. This share remains high when we specify that the mother earns less (93%). When she earns more, the share drops sharply to 47%, yet nearly half of respondents still recommend that the mother stay home. This asymmetric response rejects a purely income-based explanation of gender norms. Thus, economic circumstances shape gender attitudes, but deeply rooted norms persist even when they conflict with financial incentives.