Besides bone cancer there's also a growing link to Alzheimers. From what I've learned of it: it's used in medication due to its ability of transporting ions into the brain. It is also highly reactive with metals and flouride ions bond with metals in water supplies before being injested. The theory is that just as with medication, the flouride-metal ions pass into the brain, the largest resevoir of water in the body, and coagulate into deposits which affect cell growth. The end result is a rotting-out of the brain when, in old age, a person can no longer the replace the damaged brain cells around the metal deposits. Medical professionals only refer to "plaque" or "scar tissue" near the tiny holes in Alzheimer patients' brains, not what's under the scar tissue. Of course this is just a theory but I believe it will eventually be proven; just not in America since our media and politicians are too far under the influence of money and corporatism to care.