Only about 5% of mammalian species provide paternal care for their young. The human species is one of them, although the father has not always participated in the same way. In recent decades, as new family models emerged, the father’s involvement in the care and rearing of children has grown.
The father’s contribution to the development of his child is not only genetic, but also his participation in the care of the child in the early years, as with the mother, favors the cognitive and psycho-emotional development of the son.
It is well known that hormonal and brain changes occur in women during pregnancy and the months after childbirth to adapt to caring for the child. But does the same thing happen in the father when he assumes the care tasks? Science has shown that it is. There is evidence of similar modifications, both neuroendocrine and cerebral. Although, since research in this field is relatively recent, studies must continue to reach definitive conclusions.
Less testosterone, more oxytocin
There are several hormones that modify their levels in parenthood. Men who are fathers generally have lower testosterone levels than men who do not have children. Moreover, these levels are lower for men who are more involved in fatherhood activities, fathers of younger children, and those who spend more time with or sleep with their children. In contrast, testosterone levels increase when parents hear babies crying but cannot come to comfort them, a situation similar to a defensive or aggressive response.
Something similar happens with oxytocin, a hormone closely related to the development of the affective bond towards the child, promoting their care. This hormone increases in pregnant women at the end of gestation, is triggered during childbirth, and remains elevated for several months. Well, in the father who maintains affective contact with his baby, oxytocin levels also increase. And the same happens with other hormones such as vasopresina and the prolactin, which predispose to the care of the newborn.
The brain does not remain impassive in the face of parenthood. In a study carried out in parents using magnetic resonance imaging at 2-4 weeks postpartum (time 1) and at 12-16 weeks postpartum (time 2), it was found that the parents experienced an increase in the volume of gray matter in the regions of the brain involved in motivation and reward. Scientists suspect that we could be facing a mechanism for the functional adaptations – motivation for the care and detection of infantile signals – that parents acquire during a few months after birth. After all, this postpartum period is critical to developing an emotional bond through intense interactions.
Still, the response of primary and secondary caregiver parents is not the same. In recent research, we decided to compare three groups of fathers and mothers raising their firstborn: heterosexual primary caregiver mothers, heterosexual secondary caregiver fathers, and homosexual primary caregiver fathers raising babies without maternal involvement.
Heterosexual primary caregiver mothers showed greater activation in the brain structures for processing emotions, while heterosexual secondary caregiver parents showed greater activation in the sociocognitive network (social and cognitive understanding), related to oxytocin and synchrony between father /child.
Homosexual primary caregivers exhibited high activation of brain zones similar to heterosexual primary caregiver mothers, and high activation of brain zones comparable to heterosexual secondary caregivers. In addition, the high functional connectivity between both systems, that of emotions and that of the sociocognitive network, was verified. In all men, the time dedicated to direct child care was linked to the degree of brain connectivity.
Plasticity for the challenge of parenthood
As we have seen, the studies seem to confirm the hypothesis that the neurobiological basis of paternal care is similar to that of maternal care, although as we anticipated at the beginning, we are facing a field of study that requires more research.
The different neurobiological modifications in the parenthood process are produced thanks to brain plasticity, that is, the brain’s ability to change its structure and function throughout life, in response to the characteristics of the environment (in this case stimuli from the child and the social context), which would lead to changes in their behavior. With hormones as mediators, these changes would facilitate adaptation to the new situation, since being a father, like being a mother, entails important challenges.
Of course, it should be borne in mind that not all parents have the same conditions to live a well-being parenting. Social, economic and environmental circumstances determine to a great extent how each one can face this new stage of life.
Mª Dolores Estévez González. Pediatrician. Professor of the University School- Faculty of Health Sciences ULPGC, University of Las Palmas de Gran Canaria.
This article was originally published on ‘The Conversation’.