Motherhood Penalty—Beyond Bias? From Stereotypes to Substitutability Structures

Abstract Mothers continue to experience lower wages and slower career progression than fathers. Are mothers penalized due to prejudice or due to the costs of family-friendly work conditions? Our review of experimental studies on motherhood bias reveals a paradox: implicit bias against mothers is evident in many US and European studies, but absent in Scandinavian experimental studies; yet, mothers still face a wage and career gap. We revisit explanations related to social structures and gendered work–family specialization, including Goldin’s theory of exponential rewards for time and availability. By reviewing longitudinal Scandinavian studies and exploring the role of individual competition in particular job markets, we offer a nuanced understanding of flexibility and substitutability. Finally, we outline a shift in the theoretical lens for examining and challenging the wage and career gap—from stereotypes to substitutability structures—and introduce a model predicting the relation between individualized versus collective substitutability structures and the degree of individual and/or gendered costs.