One new study from nature.com indicates that the length of time that a baby may stare at a person in his early months could be related to an autism diagnosis later on.

When and how long a baby looks at other people’s eyes during the early months offers the earliest behavioral sign to date of whether a child is likely to develop autism later, scientists are reporting in a new study published online at nature.com.

In the study, infants who later developed autism began spending less time looking at people’s eyes between 2 and 6 months of age and paid less attention to eyes as they grew older. By contrast, babies who did not develop autism later on looked increasingly at people’s eyes until about 9 months old, and then kept their attention to eyes fairly constant into toddlerhood.

Babies whose eye fixation fell off most rapidly were the ones who later on were the most socially disabled and showed the most symptoms of autism. That an early indicator of autism may be the length of time a baby will look at someone could one day translate into a tool for early identification of children with autism.

According to the Centers for Disease Control and Prevention, the diagnosis of autism has increased from one child in 150 in 2002 to one in 88 in 2008. The reasons are unclear, although some factors could be greater awareness of the disorder and a growing number of older parents (children born to older parents are at a higher risk for ASDs, or Autism Spectrum Disorders).