I have 5 children all of whom have diagnosed thyroid disease. My husband and I also have diagnosed thyroid disease. There is no family history for our thyroid disorder. We believe that the fluoride in the water has interfered with the necessary absorption of iodine leading to a ruined thyroid gland. Iodine is needed by the thyroid and other tissues in the body. Fluoride like iodine is a halide and they are very similar in properties. So similar that the fluoride can displace iodine in tissues (thyroid disease is only one result of this process). Fluoride is a poison to such tissues while iodine is needed for life.