It has been clearly demonstrated that fluoride prevents cavities in the teeth of children, and there has been a remarkable decline in the number of cavities in children in this country since tap water has been fluoridated and fluoride toothpaste has been introduced. The issue is whether or not kids should get supplemented before they are exposed to tap water and toothpaste. It was initially believed that there was a benefit to having fluoride present even before the teeth erupt. But recent studies have suggested that there isn't any benefit until after the teeth are visible.
The other issue is the effect of taking too much fluoride. While this doesn't harm the teeth in any mechanical way, it can cause an unsightly white stain on the teeth that is difficult to cover up. Children who both drink fluoridated tap water and take fluoride supplements have had an increased incidence of this problem, which is know as fluorosis.
There have been calls within the medical and dental communities to retract the current recommendation to supplement infants or young children with fluoride. Given the current use of fluoridated water as well as fluoride toothpaste and dental rinses, most children are expected to get enough fluoride at the proper time to continue to help prevent the development of cavities. As of this time, there has been no formal change in the recommendations that the American Academy of Pediatrics gives about fluoride, but this is likely to change.
Make sure you understand how to properly care for your child's teeth once they have come in. Your pediatrician can review this for you at your next visit, and the American Academy of Pediatric Dentistry recommends scheduling a child's first dentist visit within 6 months of the appearance of the first tooth, or by 12 months of age.