Testosterone Levels, Challenging Parenting Behavior, and Protective Parenting Behavior: A Correlational Study Among First-Time Fathers in the First Year of Fatherhood.

Only few studies have examined whether testosterone levels are involved in parenting behaviors other than sensitivity and nurturing behavior. This preregistered study examined associations between fathers' hair testosterone levels, challenging parenting behavior (CPB), and protective parenting. Seventy first-time partnered fathers with a healthy-born infant (M = 6.70 months, SD = 2.16) visited our research center for hormonal and behavioral assessments. Hair samples were collected to measure testosterone concentrations over the past month. CPB was observed during father-infant free play interaction and coded for the extent to which fathers verbally and physically challenged their infants to act outside their comfort zone. Paternal sensitivity was independently rated and analyzed exploratively. Protective parenting behavior was observed during the auditory startling task, which involved exposing the dyads to a short, unexpected loud sound. No significant correlations between fathers' hair testosterone levels, CPB, and protective parenting emerged. Exploratory analyses (not preregistered) showed that fathers with lower testosterone levels were more sensitive. Future studies with larger and more diverse samples may benefit from incorporating multiple testosterone indices (e.g., hair, diurnal, and reactivity measures) to examine whether these indices are differentially related to CPB and protective parenting.