The underrepresentation of women in mathematics-related careers remains a pressing concern. While a vast literature studied the impact of starting a family on women’s employment in general, few studies examined how parenthood affects mathematical career choices from a long-term perspective, taking into account traditional gender role beliefs and prior mathematical achievement. We examined mathematics-related career choices from adolescents’ aspired careers, until their actual careers at average age 33 (N = 300; 168 women). Repeated-measures ANOVA explored whether career choice changed differentially for gender, parenthood and gender × parenthood groups. Despite a significant three-way interaction, only gender significantly affected mathematical career trajectory; males scored higher overall. However, an increase in mathematics-related career choices did approach significance, for women who had no children. Prior mathematics achievement and traditional gender role beliefs were tested as potential explanations in career trajectories. There were no group differences on prior mathematics achievement, but men who had children held more traditional gender role beliefs than women who did not. Yet, only prior mathematics achievement emerged as a significant covariate, indicating that traditional gender role beliefs did not explain the trend for increasing mathematical career choices for women without children over time. Mathematical career choices also did not decrease for women with children, counter to our prediction. Practical implications and future research recommendations are discussed.