Yes. Children are categorically external parties: they cannot choose to participate in, exit, or negotiate the conditions of their upbringing. Parental and state decisions impose irreversible costs on the child as an external party. ΔK_human is deeply negative from adverse childhood experiences; childhood blood-lead at 10 μg/dL reduces IQ by 2–5 points with documented downstream crime and earnings effects; iodine deficiency during pregnancy costs 10–15 IQ points at a brake cost of ~US$0.05/person/year for salt iodisation. Heckman's estimates of US$7–13 return per dollar on high-quality early childhood programmes clear the cost-effectiveness test comfortably. Verdict: brake environmental and nutritional externalities imposing costs on children.