Long-term effects of father involvement in childhood on their son's physiological stress regulation system in adulthood.

Using a long-term prospective longitudinal study of U.S. men and their fathers, the present study examined the extent to which the quantity (i.e., shared activities between fathers and sons) and the quality (i.e., assessors' ratings of fathers' positive behaviors toward sons and the relationship quality between fathers and sons) of father involvement during childhood influenced sons' diurnal patterns of salivary cortisol in adulthood (late 30s) directly and indirectly through substance use across the 20s. Findings indicated that the quantity of father involvement during childhood was directly associated with sons' diurnal cortisol patterns assessed almost 30 years later. Specifically, the quantity of father involvement in childhood significantly increased the intercept (i.e., upon awakening) and also led to a greater reduction in cortisol across the day, suggesting a well-regulated diurnal cortisol pattern. The quantity of father involvement significantly reduced the amount of sons' illicit drug and tobacco use across the 20s. Tobacco use across the 20s was associated with a lower cortisol intercept level (upon awakening), although the mediating path was not significant. The present study provided empirical evidence demonstrating long-term physiological and behavioral consequences of father involvement in childhood and its potency as a crucial early caregiving environment for sons.