In Japan, the gender gap in attendance at 4-year universities is narrowing, yet significantly fewer women apply to selective colleges. A growing body of literature suggests that gendered expectations of educational returns and cultural stereotypes, most compellingly reflected in parental influence, are pivotal in shaping children's college choices. However, the capacity to make causal claims remains limited in existing research, as observed gendered preferences among parents may merely echo earlier educational investments made before college applications. This study advances the field by leveraging a survey experiment approach. Our conjoint experiment, where respondents evaluate hypothetical college choices of fictitious children, yields several key findings. First, responses show no difference when the children, regardless of their gender, opt for selective colleges. Second, the respondents who expect higher returns from college education for men than for women tend to favor their fictitious son's selective college applications. Third, fictitious daughters' college choices are rated more favorably when they conform to societal gender stereotypes. These findings underscore the potential influence of recent admissions reforms in Japanese universities, including explicit quotas for female applicants, aimed at increasing their enrollment.