The central question we addressed was whether mothers' adjustment might vary systematically by the developmental stages of their children. In an Internet-based study of over 2,200 mostly well-educated mothers with children ranging from infants to adults, we examined multiple aspects of mothers' personal well-being, parenting, and perceptions of their children. Uniformly, adjustment indices showed curvilinear patterns across children's developmental stages, with mothers of middle-schoolers faring the most poorly, and mothers of adult children and infants faring the best. Findings based on children in mutually exclusive age groups--for example, mothers with only (1 or more) infants, preschoolers, and so forth--had larger effect sizes than those based on the age of the mothers' oldest child. In contrast to the recurrent findings based on children's developmental stages, mothers' adjustment dimensions showed few variations by their children's gender. Collectively, results of this study suggest that there is value in preventive interventions involving mothers not just in their children's infancy and preschool years, but also as their children traverse the developmentally challenging years surrounding puberty.