Kennedy Jr. insists an environmental toxin is responsible for increased autism prevalence in the U.S. "This is a preventable disease," he said April 16, dismissing an HHS agency report’s explanation for the increase.

Robert F Kennedy said people with autism "will never pay taxes, they'll never hold a job, they'll never play baseball," in remarks that are now being criticised.

The autism study is planning to link confidential data "with broad coverage in the U.S. population" in one place for the first time.