International Agency for Research on Cancer
“Fluoridation of drinking-water was introduced in the USA in 1950, and thus the studies in the USA encompass periods of observation of 20 years or more. … The studies have shown no consistent tendency for people living in areas with high concentrations of fluoride in the water to have higher cancer rates than those living in areas with low concentrations or for cancer mortality rates to increase following fluoridation.”
“Since a large number of comparisons were made, some would be expected by chance alone to show differences. However, no consistent difference has been seen, and there have been as many significant negative associations between fluoridated water supplies and cancer incidence or mortality as there have been positive associations.”
“… Epidemiological studies have shown no association between the presence of fluorides in drinking-water and the incidence of Down’s syndrome.”