Dr. John Yiamouyiannis,

Very old but worth watching again. Shame he died so young.

Quack watch says this

"Dr. John Yiamouyiannis,
Fluoridation Opponent, Dead at 58
Stephen Barrett, M.D.
John Yiamouyiannis, Ph.D. (1943–2000) liked to call himself "the world's leading authority on the biological effects of fluoride." [1] He was for more than 25 years the most active antifluoridationist in the United States. He was very bright—and determined. Had he chosen a positive direction, he might well have made a valuable contribution to science. But he did not. Despite training as a biochemist, he became obsessed with the idea that water fluoridation is dangerous."

He was a biochemist - not despite training as a biochemist.

Fluoride was definitively identified as an endocrine disruptor in a 2006 report by the U.S. National Research Council of the National Academies (NRC).

In summary, evidence of several types indicates that fluoride affects normal endocrine function or response; the effects of the fluoride-induced changes vary in degree and kind in different individuals. Fluoride is therefore an endocrine disruptor in the broad sense of altering normal endocrine function or response, although probably not in the sense of mimicking a normal hormone. The mechanisms of action remain to be worked out and appear to include both direct and indirect mechanisms, for example, direct stimulation or inhibition of hormone secretion by interference with second messenger function, indirect stimulation or inhibition of hormone secretion by effects on things such as calcium balance, and inhibition of peripheral enzymes that are necessary for activation of the normal hormone