14 DAY TRIAL // The results of a new scientific study appear to indicate that men and women share an equal natural inclination towards rearing and taking care of their children. These conclusions go against decades of established data saying that only women evolved to display this type of behavior.
Details of the investigation were published in the September 12 issue of the esteemed journal Proceedings of the National Academy of Sciences (PNAS). The work focused on analyzing men's hormone levels at specific moments in their lives.
Similar to women, men also experience a decrease in the amounts of testosterone in their bodies once they enter stable relationships, get married or have children. This suggests an evolutionary adaptation to fathering and caregiving, something that few experts suspected before this study.
Priorities men display when they are not involved in such activities change at the same time that their social duties shift to parenting. The team behind the new study was equally as surprised to learn about this correlation, the US National Science Foundation (NSF) reports.
“Fathers who are the most involved with physically taking care of their children have the lowest testosterone,” explains study research Lee Gettler, who was also the lead author of the new paper.
“What we see in our research is that men are biologically attuned to being caregiving parents and that they respond to the transition to fatherhood with large declines in testosterone,” adds the scientist, who is also a PhD candidate at the Northwestern University Department of Anthropology, in Evanston.
This correlation has been known to scientists for quite some time. However, the other studies failed when the time came for researchers to study these links in the long run. Most of them opted for a snapshot view of the situation, at a given time.
As such, those studies “were not able to establish whether fatherhood lowers testosterone, or whether men who had lower testosterone to begin with were more likely to become fathers,” Northwestern associate professor biological anthropology Christopher Kuzawa explains.
The 600 men who participated in the new research were selected from the Cebu Longitudinal Health and Nutrition Survey, and were followed for many years. The NSF Biological Anthropology Division, in Arlington, Virginia, provided the funding needed for the investigation.
“The research speaks strongly to the complex and interesting interplay between biology and behavior in our species. This includes the fascinating flexibility characterizing a very adaptive set of interrelationships between human physiology and social and cultural variation,” Carolyn Ehardt says.
The expert holds an appointment as an NSF physical anthropology program manager at the BAD.