Based on Gary Becker's analytical tools—the family production model and the interdependent preferences—for family economics and the later criticisms regarding Becker's auxiliary assumptions, the study attempted to answer how American people's calculation of perceived benefits and costs could mediate the effects of economic factors and gender ideology regarding their parental leave norms during the pre-birth period. With data collected through an online survey on MTurk, the study revealed that male respondents in the survey included both the economic factors and gender ideology in calculating their expected gain and loss of family well-being in taking care of the children. For female respondents, only the gender ideology entered their functions of perceived utility. Moreover, regarding the choice of exiting work for full-time parenting, there was a partial mediating effect existed between male respondents' perceived benefits and their economic factors. By comparison, both perceived costs and benefits for female participants partially mediated the effect of gender ideology.