That perception may soon change. Some in the field say it's the beginning of a wave of scientific reports that should strengthen some theories, jettison others and perhaps even herald new drugs.

The effort has been infused with new urgency by a recent federal report that found autism disorders are far more common than was previously understood, affecting 1 in 88 U.S. children. Better diagnosis is largely responsible for the new estimate, but health officials said there may actually be more cases of autism, too.

If autism's causes remain a mystery, "you're not going to be able to stop this increase," said Irva Hertz-Picciotto, a researcher at the University of California, Davis who is leading a closely watched study into what sparks autism disorders.