Abstract
This preregistered study investigated whether human paternal testosterone levels predicted fathers' time spent with their child and their involvement in childcare and household tasks. Additionally, we examined whether associations were mediated by fathers' attitudes toward child gender stereotypes. Associations were tested in an exploratory sample (n = 70, M = 6.73 months postpartum, SD = 2.13) and a test sample (n = 80, M = 2.67 months postpartum, SD = 0.77). Testosterone was quantified from the 1-cm hair segments closest to the scalp. Fathers reported on the amount of time spent with their child and on their attitudes toward child gender stereotypes. Mothers and fathers reported on fathers' involvement in childcare and household tasks. In the exploratory sample, testosterone levels were positively associated with involvement in childcare and household tasks but unrelated to the time spent with the child. In the test sample, testosterone levels did not predict the time spent with the child or involvement in childcare and household tasks. In both samples, no evidence was found for mediation by attitudes toward child gender stereotypes. In conclusion, testosterone levels are differently but not systematically associated with involvement in childcare and household tasks during the first year of fatherhood.