Genes Trump Momma in the Moses Basket

Here’s something for all you mothers and fathers who know what it's like trying to console a screaming infant in the dead of night: Your cooing, rocking, swaddling, and all other attempts to pacify your child – they’re ineffective, even irrelevant, in how he or she will react to the stressul situation, say hunger or sleepiness.

A baby’s response to stress is pretty much hard-wired until after 6 months. It’s in the genes according to a study in September's Child Development. A team of researchers from North Carolina and Pennsylvania separated babies from their mothers at 3, 6, and 12 months to induce a stressful situation then measured the babies’ cardiac responses to the stress ( “vagal tone” – for all you medical types). The researchers, okay, research assistants, also took samples of the babies’ DNA to see if they had a form of a dopamine receptor gene linked to both decreased cardiac response and risky behaviors in later life. Mother-child interaction was also taped to assess maternal sensitivity, in other words, how attentive, warm, and loving they were towards their babies. At 3 and 6 months, babies reacted to the separation in line with their genetic predisposition. Those who shared the “risky” gene showed an ineffective cardiac response, those without it, the normal response. Their mother’s sensitivity had no effect. But by 12 months, moms started to matter. The risky-gene babies with sensitive mothers showed the effective response, those with insensitive mothers showed the counter-productive response.

Does this mean you can cease all efforts to console your newborn? Hardly. This study looked at one specific physiological response. There are likely countless others linked to care giving. Obviously, parenting behavior at some point impacts children’s physiological development, here, in terms of physical reaction to a stressful situation. I find this refreshing evidence that parents don’t need to freak early on when, let’s face it, there’s plenty of challenges. Perhaps it’s nature’s infinite wisdom, the mechanics of evolution, say, that fortunately don’t leave a newborn’s health and well-being completely at the mercy of an inexperienced, sleep-deprived, and sometimes plain exasperated parent.

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