Exploring the Links between Early Life and Young Adulthood Social Experiences and Men’s Later Life Psychobiology as Fathers

Early life cues of environmental harshness and unpredictability have been hypothesized to influence within-species variation in the timing of life history transitions and the dynamics of reproductive strategies, such as investments in mating and parenting. It is also believed that adolescence is an influential developmental period for male reproductive strategies, with those who achieve greater social and sexual success during that period maintaining faster life history strategies into adulthood. If correct, such early life and post-pubertal experiences could also help shape the psychobiological pathways that mediate reproductive strategies, including the well-documented physiological shifts that occur when some men become parents. Drawing on a large sample of Filipino men (n = 417), we evaluate whether men who experienced cues of harshness or unpredictability in childhood or have earlier ages at sexual debut have elevated testosterone (T) as fathers. We also test whether males who experienced a combination of early life experiences of harshness or unpredictability and had earlier ages of sexual debut during adolescence had the most elevated T as fathers. We found that fathers who experienced early life harshness and who engaged in sex at an earlier age had elevated waking T. Among men transitioning to fatherhood across the 4.5-year follow-up period of this study, those who experienced unpredictability and who engaged in sex at an earlier age showed attenuated declines in waking T between baseline and follow-up. Complementing these findings, we found that fathers who first engaged in sex at later ages had greater acute declines in T when they played with their toddlers. We suggest that these patterns could reflect programming effects of sociosexual experiences during the years following the marked biological transitions that accompany puberty, which occur along with the better-studied effects of earlier life exposures to stressors. Overall, our results support the hypothesis that early life circumstances and social and sexual experiences, from early life to young adulthood, help calibrate physiological axes as key mechanisms coordinating dynamic life history strategies

Exploring the Links between Early Life and Young Adulthood Social Experiences and Men’s Later Life Psychobiology as Fathers

Early life cues of environmental harshness and unpredictability have been hypothesized to influence within-species variation in the timing of life history transitions and the dynamics of reproductive strategies, such as investments in mating and parenting. It is also believed that adolescence is an influential developmental period for male reproductive strategies, with those who achieve greater social and sexual success during that period maintaining faster life history strategies into adulthood. If correct, such early life and post-pubertal experiences could also help shape the psychobiological pathways that mediate reproductive strategies, including the well-documented physiological shifts that occur when some men become parents. Drawing on a large sample of Filipino men (n = 417), we evaluate whether men who experienced cues of harshness or unpredictability in childhood or have earlier ages at sexual debut have elevated testosterone (T) as fathers. We also test whether males who experienced a combination of early life experiences of harshness or unpredictability and had earlier ages of sexual debut during adolescence had the most elevated T as fathers. We found that fathers who experienced early life harshness and who engaged in sex at an earlier age had elevated waking T. Among men transitioning to fatherhood across the 4.5-year follow-up period of this study, those who experienced unpredictability and who engaged in sex at an earlier age showed attenuated declines in waking T between baseline and follow-up. Complementing these findings, we found that fathers who first engaged in sex at later ages had greater acute declines in T when they played with their toddlers. We suggest that these patterns could reflect programming effects of sociosexual experiences during the years following the marked biological transitions that accompany puberty, which occur along with the better-studied effects of earlier life exposures to stressors. Overall, our results support the hypothesis that early life circumstances and social and sexual experiences, from early life to young adulthood, help calibrate physiological axes as key mechanisms coordinating dynamic life history strategies

A–B: Changes in PM T between baseline (2005) and follow-up (2009).

<p>Analyses were restricted to men who transitioned from being non-fathers in 2005 to parents in 2009. Values are adjusted for time of saliva collection, stratified according to whether fathers were solitary sleepers (n = 9) or cosleepers (n = 200). Statistical comparisons reflect that cosleeping fathers had a significantly greater decline in PM T compared to solitary sleeping fathers. *** p = 0.001. Error bars indicate s.e.m.</p

A–B: Values of follow-up (2009) AM T (1A) and PM T (1B).

<p>Values are adjusted for time of saliva collection and are derived from regressing T on familial sleeping arrangements, controlling for covariates, with solitary sleeping fathers as the comparison group (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0041559#pone-0041559-t002" target="_blank">Table 2</a>). * p<0.05. Error bars indicate s.e.m.</p

Follow-up (2009) PM T, stratified by sleeping arrangements and whether men were fathers of infants.

<p>White bars indicate fathers without infant-age children. Gray bars indicate fathers with infants. Sample sizes listed in parentheses. Statistical comparisons reflect one-way ANOVA of hormonal values, with Bonferroni multiple comparison tests. Values are adjusted for time of saliva collection. Comparison group: solitary sleeping fathers without infants. ** p<0.01, * p<0.05. Error bars indicate s.e.m.</p

Predicting diurnal change (Δ) in 2009 testosterone (T) from paternal sleep location^a.

a<p>values are β ± SE of ΔT adjusted for sampling time.</p>b<p>excluded comparison group: fathers who slept separately from their children.</p>c<p>excluded comparison group: fathers without an infant.</p

Predicting follow-up (2009) testosterone (T) from paternal sleep location^a.

a<p>values are β ± SE of T adjusted for sampling time.</p>b<p>excluded comparison group: fathers who slept separately from their children.</p>c<p>excluded comparison group: fathers without an infant.</p

Descriptive statistics.

a<p>results of ANOVA or Fisher's exact test unless indicated otherwise. All variables reflect 2009 data.</p>b<p>highest grade completed.</p>c<p>results of negative binomial regression.</p>d<p>results of Poisson regression.</p>e<p>since 2007.</p>f<p>number of days per week that subject reported feeling rested at waking.</p

Diurnal change (Δ) in T at follow-up (2009).

<p>Values are derived from regressing ΔT on familial sleeping arrangements, adjusting for covariates, with solitary sleeping fathers as the comparison group (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0041559#pone-0041559-t003" target="_blank">Table 3</a>). * p<0.05. Error bars indicate s.e.m.</p