"Toxic weedkiller" -- define "toxic". Anything is toxic in high enough amounts, the question is whether the amounts detected surpass that threshold for glyphosate. (Also, I believe in toxicology, "toxic" and "carcinogenic" mean two very different things; this article mentions carcinogenicity, not actual toxicity.) Since there is no mention of either the carcinogenic risk per gram nor how much of it was detected in the children's bodies, there's no reason to freak out or assume they're poisoned/cancerous as a result.