Fatherhood & Health:

Fatherhood - Evolution and Human Paternal Behavior
P B Gray & K G Anderson; 2012

Fatherhood appears to have both protective and deleterious impacts on men's health. The parenting of young children tends to negatively impact marital quality, meaning that men lose some of the beneficial effects of affiliative pair-bonds. Male mental health may suffer, especially if his partner is also struggling with mental health difficulties. Sleep and sexual challenges may exacerbate these difficulties. Young children, particularly those in daycare, can also serve as disease vectors (for example, Hillis et al. 1992), presenting a father with greater exposure to transmissible diseases. The outcome of these types of issues is that fathers of young children may have compromised health.

Yet as those children age, men's health may rebound. The strains of caring for young children wane. Those children may provide social and material support to aging parents. Perhaps an older father, living somewhere without a Social Security check to cash, is supported partly by the sons or daughters he raised to adulthood. Put all of these health and fatherhood variables together, and maybe observations like the following make sense. As shown in a U.S. study of approximately five thousand adults, the effects of fatherhood altered across a man's life and his children's ages (see E. E. Bartlett 2004). In this large U.S. study, among married men aged forty years or younger, 8.9% of fathers but only 1.1% of married men without children rated their health as fair or poor. In the same study, among married men aged forty-one to sixty-four, 16.5% of married fathers with children but 22.7% of married men without children rated their health as fair or poor. Similarly, in an Australian study, fathers of preschool-aged children reported worse health than fathers did of older children (Hewitt, Baxter, and Western 2006). These data suggests that earlier in life fatherhood may be a drain on a man's health, but that same relationship may have later, beneficial effects. This pattern appears to be the overarching perspective on fatherhood and health.

[This excerpt doesn't seem to be based on very hard data, but I think it makes some interesting points.]