Comment by 0xbadcafebee

1. IQ is not an objective measurement, it is inherently flawed

2. A 1.5-3 IQ level difference is not noticeable in any practical way. Things like birth order have a more significant impact on IQ.

3. Comparing Canadian children to Mexican is pretty dramatic, like comparing rich kids to poor kids; you will always see a marked difference between the two, in intelligence, in health, in crime, in all sorts of things. Mexican communities often over-fluoridate their water (I know because I grew up in Mexico and my teeth are stained because of it). Again, this is no reason to ban it, just lower it.

This finding is a suggestion of a link, it's not empirical proof. The methods and findings have many questionable aspects. You can always find some paper that suggests something random like vegetables are bad for you or something. One paper does not a water-tight case make.