IF THE FIGURE of “one in 166” has a familiar ring, perhaps that's because you recently heard it on a television commercial or read it in a magazine. According to widely publicized estimates, one in 166 is now the proportion of children who suffer from autism. This proportion is astonishingly high compared with the figure of one in 2,500 that autism researchers had accepted for decades. Across a mere 10-year period—1993 to 2003—statistics from the U.S. Department of Education revealed a 657 percent increase in the nationwide rate of autism.