The child sets the rules too

The usual story about difficult children runs one way. Parents who enforce rules unevenly get children who hit, defy and shout. A study published in Nature Communications, led by Joanna K. Bright of King’s College London, tested that story against two large, genetically informative samples, and the arrow mostly pointed the other way¹.

The two samples. The first is Norway’s Mother, Father and Child Cohort, with extended-family data on 53,532 children born to 42,538 mothers, assessed at age five¹. The second is the US Early Growth and Development Study: 561 adoption triads of an adopted child, the adoptive parents and the birth parents, followed from 4.5 to 8 years¹. Adoptive parents share no genes with the child, which lets you see the family environment without inheritance getting in the way¹.

What they found. In Norway, about 47% of the modest link between inconsistent discipline and aggression came from shared genes; the rest pointed from child to mother, with no significant path from discipline to aggression¹. The adoption study agreed: a child’s aggression predicted more inconsistent discipline at later ages, while mothers’ discipline did not significantly predict later aggression¹. The authors write that “childhood aggression drives inconsistent parenting beyond shared genetic influences”¹. The link between warm, positive parenting and lower aggression was, in Norway, fully explained by shared genes¹.

The caveats. The measures were narrow and mostly mothers’ reports; the families were relatively advantaged; the data are 10 to 23 years old¹. With fathers’ own reports, the influence ran both ways at the same age¹. And when one parent rated the child and the other rated the parenting, the links vanished, which hints that one person reporting both inflates them¹.

The constructive reading. None of this says parenting does not matter. It says a parent worn down by a child who pushes back is not simply the author of the pushing. The authors suggest that programmes that only coach consistent discipline “may be insufficient”¹. Help that works with the child’s behaviour as well as the parent’s is a less tidy message, and probably a kinder one. Nothing here is advice.