Is it true that fluoride can cause cancer?

Yes. In 1990 fluoride was found to be an equivocal carcinogen by the National Cancer Institute Toxicology Program.

(Maurer, et. al.,"Fluoride an equivocal carcinogen. J.National Cancer Institute 82, 1118-26, 1990)

In 1992 further studies by the New Jersey Department of Health confirmed a 6.9 fold increase in bone cancer in young males.

(Cohn, Perry D. Ph.D. "An Epidemiological Report on Drinking Water" Fluoridation and Osteosarcoma in Young Males, New Jersey Department of Health, Environmental Health Service, Trenton NJ November 8, 1992)

In 1997 there were more than 80 references available, linking fluoride to cancer.