Augustine astutely quashed the 5th century pagan contention that Christian belief is both superstitious and barbaric. Science, he pointed out, can and should be used to clarify and illuminate the Christian faith. In Fides et Ratio, John Paul II not only echoed this insight, but also insisted on its complimentary reverse. Faith can help scientists discover the meaning and ethos of their empirical investigations and discoveries.
In this light, I recently read the results of a large, representative study on male hormones and social behavior (Lee Gettler et al, “Longitudinal evidence that fatherhood decreases testosterone in human males,” [PNAS, 2011]). The study’s data show that the physiology of male hormones has evolved to facilitate a father’s caregiving toward his children.
The researchers underscore the verb, facilitate. There are, after all, deadbeat dads and abusive fathers out there. So, while the physiological mechanisms of the male neuroendocrine system can give a biological boost to the father’s efforts at raising his children, only the father’s free decision, choice, and actual provision of the care gets the job done.
The findings of the Gettler study cry out for an evaluation through the lens of Christian anthropology and theological ethics. My reflection answers the question: What’s the study’s Catholic take-home message for natural (biological) fathers?
The Study and What It Suggests
Prior to the Gettler study, other smaller surveys had already demonstrated that fathers have lower testosterone (T). But, since these earlier investigations were cross-sectional, measuring “snapshots” in time, they couldn’t definitively prove whether it was fatherhood that brought T down or whether lower-T males were just more likely to become fathers.
The Gettler study, in contrast, took a longitudinal approach by studying a large group of men who lived in or around Cebu City, Philippines where it is customary for fathers to be involved in the everyday care of their children. It followed 624 men and measured testosterone levels at 21.5 (baseline) years of age, and again, after they had become fathers 4.5 years later, when they were 26 (follow-up).
Does dating-related behavior elevate male T levels? and Does childcare-related behavior depress male T levels?
This study’s data showed:
- Single non-fathers with higher testosterone levels at baseline were more likely (than those with lower baseline levels of T) to be newly-partnered and newly-partnered-new-fathers at follow-up;
- Men who were both newly-married and new fathers at follow-up showed the largest declines in T, more than double that of single, non-father participants at follow-up;
- All new fathers, regardless of their youngest child’s age, experienced a significant reduction in T compared with non-fathers, while fathers with newborns at the time of follow-up showed significantly greater declines in T compared with fathers whose youngest child was older than 1 year of age
- Fathers providing the greatest childcare output (3+ hours per day) had lower T levels than fathers providing lesser parenting care.
If we evaluate the findings of the Gettler study from the side of evolutionary biology and anthropology, they suggest that biology and behavior exert bi-directional influences on one another.
First, elevated testosterone levels in a single, fatherless male could be predictive of his mate-finding success. Increased testosterone, in other words, facilitates assertiveness and competitiveness with other single males and enhances the male’s physical condition: better health, better looks (stronger muscles, bigger body), collectively making the man more attractive to, and more apt to win over, a female partner.
Second, downregulation of T in married fathers facilitates fatherly caregiving and husbandly commitment and is, in this sense, predictive of the father’s parenting success. The human partnered father, has an evolved “neuroendocrine architecture” shaped to facilitate his role as husband and father. As one anthropologist explains it: “a dad with lower testosterone is maybe a little more sensitive to cues from his child, and maybe a little less sensitive to cues from a woman he meets at a restaurant.”
Third, human parental care is so important—and demanding—that it has shaped the neuroendocrine physiology of both mothers and fathers. Since children are totally dependent on parental care for at least the first decade of their lives, they require “raising” by both parents, in a cooperative, bi-parental fashion. In short, the data of the Gettler study supports the nostrum that children need a mommy and a daddy.
Fourth, the Gettler study data reinforces the evolutionary biologist’s notion of how male “investment” in children also, and at once, benefits the wife and mother as well as the family unit. Direct forms of a married man’s parenting include provision of food, shelter, protection, and other resources for the child; indirect forms include social-emotional support of his wife, maintenance of the home, and acquisition of adequate material family-supportive resources.
The sum of these efforts not only dramatically (1) enhances children’s chances for survival and reproductive success but also (2) promotes the mother’s well-being and protection, allowing her to conserve her energy for future attempts at pregnancy, and (3) stabilizes and enriches the family unit.