This paper examines intra‐household allocation of resources to gain insight into family relationships and gender bias in Japanese households. We take the Engel curve approach to examine how adult consumption is affected by the presence of a child, either a boy or a girl, in the family. Empowered by diary‐based high quality spending data from the Family Income and Expenditure Survey, our empirical results show that adult consumption is significantly reduced in households with children; furthermore, gender bias is not observed in total adult expenditures, while responses of adult clothing expenses to the presence of a child are significantly different between a boy and a girl: spending on a father's clothing is reduced when the child is a school‐aged daughter, while spending on a mother's clothing decreases when a school‐aged son is in the home. Our analysis also shows that after the early 2000s girls receive a larger share of spending for children's clothing as well as for high school education than boys.