An anonymous reader writes "Defining and diagnosing autism has been a controversial process — but may be a little less so now. Children with autism have a different chemical fingerprint in their urine than non-autistic children, according to new research. The difference stems from a previously documented difference in gut bacteria found in autistic individuals. The possibility of a simple pee test matters because currently, children are assessed for autism through a lengthy testing process that explores a child's social interaction, communication, and imaginative skills. Being able to identify the condition earlier and at a lower cost could leave more time and money for treatment."