Despite evolving parental roles, moms are often the primary subject of scientific studies designed to determine how kids are affected by a parent’s social, mental, financial, and physical health. There’s even a well-quoted saying that embodies how mom’s moods and outlooks affect her brood: if Mom’s not happy, nobody’s happy. A new study from Michigan State University published in both Early Childhood Research Quarterly and Infant and Child Development, however, found that the moods and stress levels of fathers play a more crucial role than previously believed — and that their contribution to kids’ cognitive, language, social, and behavioral outcomes deserves a closer look. The study, which included 730 mostly low-income families across the country, found that kids (and male children in particular) had poorer language skills at age three when dad’s mental health and stress levels suffered. This was the case even when the mother had a positive influence on the child and environment. Both boys and girls scored lower on tests studying cognitive abilities including learning and reasoning. Father’s mental health also had potentially long-lasting social effects on their children, impacting skills such as self-control and cooperation when the children were in fifth grade. Additionally, both parents’ mental health had a similarly significant impact on behavior problems in toddlers. Children of dads who were chronically stressed or had symptoms of depression tended to have more behavioral problems later in childhood as well. Pointing to other studies that have shown that fathers interact differently with kids than moms do and have a differing approach in regards to cultivating language development, researchers stressed the importance of the father’s role in the family’s health dynamics… and the need for fathers to take care of their well-being for the benefit of everyone.