A study published in The Proceedings of the National Academy of Sciences (PNAS, September 12, 2011) may seem to be saying fathers be very afraid.
In a study of 624 Pilipino men, fathers who spent several hours a day giving care to their kids had a massive drop in testosterone.
The study shows that while the single men with higher testosterone levels at the beginning of the study were more likely to find partners and become fathers, new fathers experienced a drop in levels of the sex hormone greater than drops seen in men of the same age without children over the study period.
The study reveals that men who spent more than three hours a day caring for children — playing, feeding, bathing, toileting, reading or dressing them — had the lowest testosterone.
These findings may suggest a biological trade-off, with high testosterone helping secure a mate, but reduced testosterone better for sustaining family life.
Moreover, the study suggests that men’s bodies evolved hormonal systems that helped them commit to their families once children were born.
The study also implies that men’s behavior can affect hormonal signals their bodies send, not just that hormones influence behavior.
This study brings into focus one likely explanation for previously observed health disparities between partnered fathers and single men.
Married men and fathers have lower risk for certain diseases and mortality. It has been shown that high testosterone may increase risk for prostate cancer and adverse cholesterol profiles. High testosterone has also been linked to risk-taking behaviors that can affect men’s health, such as drug and alcohol use and promiscuity.
So men and not just women, could actually biologically hardwired for parenthood.