In this research, we investigate how children shape maternal marital happiness. The findings reveal that the otherwise negative effects of sibship size are altered by the gender composition of the sibling group. Having sons tends to reduce the negative impact of sibling group size. Solving for main effects in the interactions that include sibship size by the gender composition of the sibling group, we find that having all sons affords the most beneficial consequences for marital happiness. The daughter-only groups have nonsignificant effects, and the mixed-gender sibships have the most deleterious influence on maternal marital happiness. Within a subsample of mixed-gender sibships only, we further find that mothers who have more boys than girls are more likely to report higher marital gratification. Generally speaking, our research demonstrates the need to examine both main and interaction effects of family structure on marital happiness.