This could be a big step forward, because the earlier autism is detected,the better the chance for intervention.
Experts have known for a while that children on the spectrum make less eye contact than other children.
And now a team at Emory University says babies whose eye contact starts to drop between two and six months are much more likely to have autism.
In typical children, eye contact increases during that time.
By 2 years, children later diagnosed with autism focused on their mothers' eyes only half as long as typically developing children.
But the children with autism had become much more interest in objects, the reverse of what happens with typically-developing children.
In addition, interest in objects tends to decrease for kids in that age-range, however, in kids with autism, it increases.
"Autism isn't usually diagnosed until after age 2, when delays in a child's social behavior and language skills become apparent. This study shows that children exhibit clear signs of autism at a much younger age," said Thomas R. Insel, M.D., director of NIMH.
This isn't something parents alone can pick up. It takes eye-tracking technology.
And right now, experts recommend screening kids for autism between 18 months and 2 years.
The study was funded by the National Institute of Mental Health.
Researchers are conducting bigger studies on eye contact, and are trying to translate their finding into a test usable in the clinic.