Mr. Guthrie has gotten it wrong.  The Mexican study measured the fluoride in pregnant women's urine which is an accurate way to measure fluoride intake from all sources - food, water, medicines, dental products, air pollution, etc.  What's important to know is the the level of fluoride found in Mexican pregnant women's urine is linked to their offsprings' lower ingelligence. What's very important to understand is that the pregnant women's fluoride urine levels are the same as that reported in US adults who live in fluoridated areas.

And it's not just one study.  There are over 300 studies linking fluoride to neurological effects - 51 of them human.

When fluoridation began, there was no thought that fluoride would enter the brain. That fact alone should be the end of fluoridation.  Put fluoride on your teeth if you want but don't put it in children's brains.