IQ

A study published Monday suggests that fluoride consumed by pregnant women can decrease the IQ of their children. No single study provides definitive answers, but the latest research on this controversial topic will no doubt stir debate.

Fluoride protects teeth from decay, so public health officials celebrate what has been accomplished by putting it in many water supplies. But Christine Till, an associate professor of psychology at York University in Toronto, also wondered about potential downsides.

The U.S. Supreme Court ruled 12 years ago that the states could not execute the "mentally retarded." But the court left to the states the definition of what constitutes retardation.

On Tuesday, however, the justices, by a 5-to-4 vote, imposed some limits on those definitions. At issue, in a case from Florida, was how to evaluate IQ tests.