Longitudinal evidence that fatherhood decreases testosterone in human males

Abstract

In species in which males care for young, testosterone (T) is often high during mating periods but then declines to allow for caregiving of resulting offspring. This model may apply to human males, but past human studies of T and fatherhood have been cross-sectional, making it unclear whether fatherhood suppresses T or if men with lower T are more likely to become fathers. Here, we use a large representative study in the Philippines (n = 624) to show that among single nonfathers at baseline (2005) (21.5 ± 0.3 y), men with high waking T were more likely to become partnered fathers by the time of follow-up 4.5 y later (P < 0.05). Men who became partnered fathers then experienced large declines in waking (median: −26%) and evening (median: −34%) T, which were significantly greater than declines in single nonfathers (P < 0.001). Consistent with the hypothesis that child interaction suppresses T, fathers reporting 3 h or more of daily childcare had lower T at follow-up compared with fathers not involved in care (P < 0.05). Using longitudinal data, these findings show that T and reproductive strategy have bidirectional relationships in human males, with high T predicting subsequent mating success but then declining rapidly after men become fathers. Our findings suggest that T mediates tradeoffs between mating and parenting in humans, as seen in other species in which fathers care for young. They also highlight one likely explanation for previously observed health disparities between partnered fathers and single men.challenge hypothesis | human evolution | hormones and behavior | paternal care | reproductive ecology I n male mammals, testosterone (T) stimulates the development and maintenance of traits and behaviors that contribute to male mating effort, including musculature, libido, conspecific aggressivity, and courtship (1-4). Although these T-driven traits factor into mating success, male reproductive fitness in some avian and mammalian species also depends on contributions to offspring care (5, 6). Because time and energy are finite (7), males in these species often face tradeoffs between conflicting behaviors related to mating and parenting. Adjustment of T production has been proposed as a physiological mechanism underlying this tradeoff, with males who focus on mating effort predicted to maintain elevated T, whereas males who cooperate with a female partner and invest in parental care should reduce T production (6,8). This model is well supported by data from a variety of avian species (6, 8), but evidence for its applicability to mammalian species in which males provide direct care is mixed (9). It is presently unclear whether T mediates the tradeoff between mating and parenting effort in human males, who often express paternal care facultatively.Humans have been described as serial monogamists who frequently engage in one or more long-lasting partnerships with females during reproductive life spans that last several decades (10-12). Humans are one of the few mammalian species in which paternal care is relati...

Effects of exogenous testosterone and mating context on men's preferences for female facial femininity

“…Previous findings also show that T can fortify traits associated with attractiveness and mating effort, such as the pursuit of status/social dominance (e.g., Archer, 2006) or the motivation to win a competition (Salvador, Suay, González-Bono, & Serrano, 2003). Other research examining paired (i.e., in committed and/or romantic relationships) versus non-paired (i.e., not in a committed relationship) men show differences in T levels in this predicted direction such that paired men have lower T; such findings have been shown repeatedly across both cross-sectional and longitudinal study designs (Burnham et al, 2003;Gettler, McDade, Feranil, & Kuzawa, 2011;Gray et al, 2004;Gray, Yang, & Pope, 2006). Because pair-bonding reduces the need to compete for mates, lower T levels may be a consequence, or alternatively, high T-levels may help facilitate mating for the most desirable mates.…”

Men’s status and reproductive success in 33 nonindustrial societies: Effects of subsistence, marriage system, and reproductive strategy

“…A study of Hadza foragers found that men increase their production of less-widely shared foods when they have newborns in camp (59). In many societies, fatherhood is associated with a decrease in testosterone level (60). The change in testosterone may facilitate a shift not away from status seeking, but rather away from aspects of status seeking that focus on mate access and toward aspects of status seeking that focus on social network building (61).…”

When Dads Help: Male Behavioral Care During Primate Infant Development

“…For example, the in fl uence of hormones like prolactin, vasopressin, oxytocin, and testosterone in relation to bonding and infant care, or behavioral trade-offs between care and mate-acquisition have been extensively studied, even if still not completely understood (Bales et al 2004 ;Brockmann et al 2001 ;Gettler et al 2011 ;Goymann et al 2007 ;Gray et al 2007 ;Hirschenhauser and Oliveira 2006 ;Huck et al 2005 ;Schradin and Anzenberger 2002 ;Schradin et al 2003 ;Trainor andMarler 2001, 2002 ;Wing fi eld et al 1990 ;Ziegler 2000 ;Ziegler et al 1996Ziegler et al , 2000 . Differences in hormone production, responsiveness, or ontogenetic exposure may partly explain individual differences in caretaking behavior (Birnie et al 2011 ;Drea 2007 ;Ziegler et al 2009 ) .…”