Exposure to common chemicals can irreversibly weaken children's teeth, researchers have said.
Chemicals found in many plastics and fungicides may be disrupting hormones that stimulate the growth of dental enamel, they said.
Experts from the French National Institute of Health and Medical Research examined bisphenol A (BPA) - a chemical found in everyday items including refillable drinks bottles and food storage containers - and vinclozolin, which is commonly used as a fungicide in vineyards, golf courses and orchards.
Scientists gave rats daily doses of BPA alone or in combination with vinclozolin, equivalent to the average exposure humans have on a daily basis, from birth until they were 30 days old.
They then collected cells from the rats' teeth surface and found that BPA and vinclozolin changed the expression of two genes controlling the mineralisation of tooth enamel, according to the study which is to be presented at the European Congress of Endocrinology.
Dr Katia Jedeon, lead author of the study, said: "Tooth enamel starts at the third trimester of pregnancy and ends at the age of five, so minimising exposure to endocrine disruptors at this stage in life as a precautionary measure would be one way of reducing the risk of enamel weakening."