Does a man's testosterone "rebound" as dependent children grow up, or when pairbonds end? A test in Cebu, Philippines.

OBJECTIVE: Cross-culturally, men's T declines in response to pairbonding and fatherhood, but less is known about what happens to T during and after life history transitions that theoretically lead to renewed mating effort. We tested whether men's T rises (or declines less with age) as their children age, or when pairbonds end, independent of changes in fatherhood-related variables such as co-residence with children. METHODS: We used demographic, behavioral, and salivary hormone data (waking and pre-bed T) collected in 2009 and 2014 for the Cebu Longitudinal Health and Nutrition Survey (n = 571 men). RESULTS: Fathers with older children tended to have attenuated decline in pre-bedtime T between 2009 and 2014 compared to men with younger children, after controlling for pairbonding (ß = 1.58, SE = 0.88, P = 0.074). Separated men had higher pre-bedtime T than pairbonded men, controlling for fatherhood-related variables (ß = 11.74, SE = 4.33, P = 0.007). Change in T did not significantly differ for men who separated between the two surveys, relative to men who remained pairbonded throughout. CONCLUSION: We found modest support for the prediction that men experience less of an age-related drop in T as their youngest child ages, a trend that might strengthen as children age further. We also replicate the finding that separated men have higher T, although longitudinal changes in the hormone were not significantly different in these men. Our data suggest that, of two life history transitions that may predict renewed mating effort, pair bond loss is more strongly endocrine mediated than potential mating effort shifts related to the aging of children.