The first patient of the afternoon is a 4-month-old in for his health maintenance visit. You’ve known his 20-year-old mother since she was a toddler. This infant has a 2-year-old sister. Also in the exam room is a young man you don’t recognize whom the mother introduces as Jason, her new boyfriend. He never makes eye contact and despite your best efforts you can’t get him to engage.
Dr. William G. Wilkoff
At the child’s next visit you are relieved to see the 6-month-old is alive and well and learn that your former patient and her two children have moved back in with her parents and Jason is no longer in the picture.
You don’t have to have been doing pediatrics very long to have learned that a “family” that includes an infant and a young adult male who is probably not the father is an environment in which the infant’s health and well-being is at significant risk. It is a situation in which child abuse even to the point of infanticide should be waving a red flag in your face.
Infanticide occurs in many animal species including our own. As abhorrent we may find the act, it occurs often enough to be, if not normal, at least not unexpected in certain circumstances. Theories abound as to what advantage the act of infanticide might convey to the success of a species. However, little if anything is known about any possible mechanisms that would allow it to occur.
Recently, a professor of molecular and cellular biology at Harvard University discovered a specific set of neurons in the mouse brain that controls aggressive behavior toward infants (Biological triggers for infant abuse, by Juan Siliezar, The Harvard Gazette, Sept 27, 2021). This same set of neurons also appears to trigger avoidance and neglect behaviors as well.
Research in other animal species has found that these antiparental behaviors occur in both virgins and sexually mature males who are strangers to the group. Interestingly, the behaviors switch off once individuals have their own offspring or have had the opportunity to familiarize themselves with infants. Not surprisingly, other studies have found that in some species environmental stress such as food shortage or threats of predation have triggered females to attack or ignore their offspring.
I think it is safe to assume a similar collection of neurons controlling aggressive behavior also exists in humans. One can imagine some well-read defense attorney dredging up this study and claiming that because his client had not yet fathered a child of his own that it was his nervous system’s normal response that made him toss his girlfriend’s baby against the wall.
The lead author of the study intends to study this collection of neurons in more depth to discover more about the process. It is conceivable that with more information her initial findings may help in the development of treatment and specific prevention strategies. Until that happens, we must rely on our intuition and keep our antennae tuned and alert for high-risk scenarios like the one I described at the opening of this letter.
We are left with leaning heavily on our community social work networks to keep close tabs on these high-risk families, offering both financial and emotional support. Parenting classes may be helpful, but some of this research leads me to suspect that immersing these young parents-to-be in hands-on child care situations might provide the best protection we can offer.
Dr. Wilkoff practiced primary care pediatrics in Brunswick, Maine, for nearly 40 years. He has authored several books on behavioral pediatrics, including “How to Say No to Your Toddler.” Other than a Littman stethoscope he accepted as a first-year medical student in 1966, Dr. Wilkoff reports having nothing to disclose. Email him at pdnews@mdedge.com.