The first signs of autism may be visible as early as the first month of a child's life, according to a study published Wednesday in the scientific journal Nature.

"These are the earliest signs of autism ever observed," says lead study author Warren Jones.

Researchers at the Marcus Autism Center in Atlanta followed 110 children from birth to age 3, at which point a diagnosis of autism was ascertained. Fifty-nine babies were considered "high risk" for developing an autism spectrum disorder (ASD) because they had siblings with autism; 51 were considered "low risk" because they did not have first, second or third-degree relatives with ASD.

Data was collected at 2, 3, 4 ,5, 6, 9, 12, 15 and 24 months of age. Each time, the children watched videos showing actresses playing the role of a caregiver. "Every baby watched the same videos, and then we could measure what was different about the responses of infants later diagnosed with autism versus infants who were typically-developing," Jones says.

Lack of eye contact is one of the red flags when it comes to autism - a group of neurodevelopmental disorders that can cause significant social, communication and behavioral challenges.

Jones, who is the director of research at Marcus Autism Center and assistant professor in the Department of Pediatrics at Emory University School of Medicine, says he really expected the children later diagnosed with autism would have diminished eye contact from birth. Instead, he and his colleagues measures how much time each baby was looking at the eyes of the caregiver in the video.

"Basically from birth, (all) babies will look more at the eye part of faces," says Jones. But at about 4 to 6 weeks, he says the attention to eyes decreases, then in typical babies picks up again at 2 months. Jones found, "in the first 6 months of life we're seeing a decline in the amount of looking at other people's eyes in children who later are diagnosed with autism."

The research suggests that a baby's initial eye contact ability may be an almost a reflex-like behavior, but then there may be a second phase of development that depends on different brain and gene systems which lead to social interaction, Jones says. That's where a typically developing child's development may differ from a child with autism.

The study authors conclude that "the observation of this decline in eye fixation - rather than outright absence - offers a promising opportunity for early intervention."

This is not something parents are going to see by just holding their baby, Jones points out. This type of eye-tracking requires sophisticated technology that can track even the slightest movement of the eye.

"It's a very interesting study with intriguing results. " says Wendy Stone, a longtime autism researcher and director of the Research in Early Autism Detection & Intervention (READI) lab at the University of Washington. But, she adds, "many researchers in this field have not seen behaviors under 6 months to be predictive of later diagnosis."

She also cautions that babies looking at videos of their mothers are not the same as the actual stimuli created by a mom interacting with her baby. "Are these babies less interested in eyes because mouths are more interesting to look at and more attractive because there's more movements? To me that's one of the big questions," says Stone.

Dr. Max Wiznitzer, a pediatric neurologist and autism specialist at the Rainbow and Babies Children's Hospital in Cleveland, Ohio, says this new study is a continuation of previous work in babies. He says this research makes sense to him. "There's a decrease in the amount of attention to eyes as an early marker of social behavior (think of it as a primitive level of socialization)." Wiznitzer suggests the failure to establish these early social skills has ramifications later as "social behavior shifts into more sophisticated patterns."

If this research bears out, then maybe at some point a pediatric practice could track eye movements as one way to diagnose a child with autism, says Stone. "But we're really, really far away from that."

Wiznitzer says this may explain why the autism symptoms may be more apparent at 18 to 24 months, "even though 'subclinical' onset was months earlier." He also suggests these study results may offer another explanation why the measles, mumps and rubella vaccine, which isn't administered until a baby is at least 12 months old, cannot be blamed for causing autism.

Everyone agrees this research needs to be replicated in bigger studies with more children, Wiznitzer says. "The authors are correct that a replication study using a larger number (of children) is necessary. Before that time, I would not devote extensive resources towards assessing eye attention in infants or designing major intervention programs."

Jones says, "what we really want to do is create growth charts for social behavior, just like we have growth charts for charting a child's height and weight." He says these those are the kind of tools that pediatricians need and parents are looking for.