Variation in testosterone levels and male reproductive effort: Insight from a polygynous human population

Longitudinal evidence that fatherhood decreases testosterone in human males

“…Familial composition was not a confounding influence on the relationships that we documented, which is consistent with previous research from Cebu reporting that fathers did not alter their childcare participation based on their number of children (38). Together, these findings provide longitudinal support for the hypothesis that interacting with a dependent child suppresses T (20,22,24). In prior research conducted in two neighboring cultural groups in Tanzania, fathers in the population in which paternal care is the cultural norm had lower T, whereas this was not found among fathers in the group in which paternal care is absent (20).…”

“…In an experimental setting, men with greater T also reported feeling less sympathy or need to respond to infant cries compared with men with lower T (37). Although prior cross-sectional studies have led to speculation that fatherhood decreases T in human males (19,22,24), our longitudinal results demonstrate that fatherhood causes T to decline and remain low. These findings were not substantively changed when covariates (psychosocial stress and sleep quality) that might be expected to mediate the relationship between fatherhood/ marriage and T were included in models and are consistent with a previous longitudinal report that men who were married experienced decreased T (18).…”

“…In prior research conducted in two neighboring cultural groups in Tanzania, fathers in the population in which paternal care is the cultural norm had lower T, whereas this was not found among fathers in the group in which paternal care is absent (20). In a study of a polygynous Senegalese society, it was found that fathers who were highly invested in their children, as reported by the children's mothers, had lower T compared with fathers who were less invested (24). Lower T has also been associated with nurturing behaviors among fathers (37, 39).…”

“…In comparisons of men varying in both relationship and parenting status, partnered fathers have been shown to have the lowest T overall, differing significantly from single nonfathers in some populations (19)(20)(21), including the present study population (22, 23). There is also increasing evidence that caregiving predicts which fathers have lowest T (20,22,24). Although these crosssectional correlations are generally consistent with the presumed suppressive effect of partnering and fatherhood on T production (a "state" effect), such findings could alternatively result if men with low T are more likely to become partnered or fathers (a "trait" effect) (25).…”

Individual Differences in Reproductive Strategy are Related to Views about Recreational Drug Use in Belgium, The Netherlands, and Japan

“…However, women also stand to benefit from mating with men with "good genes" (Little, Connely, Feinberg, Jones & Roberts, 2011;Scheib, 2001). There is evidence of a trade-off between good genes and parental investment in men: Men with "good genes", on average, invest less in their offspring (Alvergne, Faurie, & Raymond, 2009;Booth & Dabbs 1993). Hence, "good genes" partners are less likely to be investing fathers, and women might have to choose between either a short-term encounter with a "good genes" partner or a long-term relationship with an investing partner.…”