The foetus and the child are particularly vulnerable to pollution. The foetus shares the mother’s exposure and accumulated body burden of pollutants, and some chemicals are transferred to the infant via human milk. Occurrence of severe dental fluorosis in a child, whose mother had worked at the Danish cryolite factory suggests that fluoride transfer from mother to child takes place. The central nervous system may be a target organ, as suggested by laboratory animal studies. During early life, cell differentiation, multiplication and migration must happen in a particular sequence and at certain times to create optimal brain functions of the mature organism. Thus, developmental exposure to neurotoxic substances can cause serious disease and also widespread loss of IQ. While fluoride exposure may cause neurotoxicity in adults, the evidence on developmental neurotoxicity in humans is uncertain and is mainly based on studies carried out in China. Exposures were generally assessed on a community basis, and cross-sectional examinations of neuropsychological test performance were related to water-fluoride concentrations. In humans, only five substances have so far been documented as developmental neurotoxicants: lead, methylmercury, polychlorinated biphenyls, arsenic, and toluene. From this evidence, including our own studies on some of these substances, parallels may be drawn that suggest that fluoride could well belong to the same class of toxicants, but uncertainties remain. At least 200 industrial chemicals are known to cause brain toxicity in humans, mainly in adults, and they must also be suspected to harm the developing brain. Because of the individual and societal importance of optimal brain function, recognition of developmental neurotoxicity is a public-health priority, and further evidence on fluoride is needed.