Childhood adversities have a well-established dose–response relationship with later mental health. However, less attention has been given to intergenerational influences. Further, it is unknown how intergenerational influences intersect with children’s developmental stages and gender. The current study examined whether a developmental inflection point exists when the intergenerational influences of childhood adversities gain salience and explored differences by children’s gender. Data were from the Young Women and Child Development Study (n = 361). Time-varying effect models (TVEMs) and moderation TVEMs by child’s gender were evaluated. Our findings reveal that ages 5–8, the period of transition into primary schools, may represent a developmental inflection point when the intergenerational influences of maternal childhood adversity start emerging substantially. The results from gender interaction TVEMs reveal that maternal childhood adversity was a statistically significant predictor of internalizing problems until age 11, regardless of child’s gender, and remained statistically significant for girls’ internalizing problems until age 16.7. For externalizing problems, maternal childhood adversity was a statistically significant predictor until age 13, regardless of gender.