While some children with autism may benefit from taking oxytocin, low levels of the so-called “love hormone” do not appear responsible for causing the developmental disorder, researchers say.

In the largest study yet to look at oxytocin levels in children with and without autism, researchers found that kids on the spectrum are no more likely to have low, medium or high amounts as compared to their siblings or those without autism in their families.

At the same time, however, the study published this month in the Proceedings of the National Academy of Sciences found that oxytocin levels were linked to the degree of social functioning across all children.

“Oxytocin appears to be a universal regulator of social functioning in humans,” said Karen Parker, an assistant professor of psychiatry and behavioral sciences at the Stanford University School of Medicine and the lead author of the study. “That encompasses both typically developing children as well as those with the severe social deficits we see in children with autism.”

Often called the “love hormone,” oxytocin is naturally-occurring and plays a role in childbirth, helping mothers bond with their babies and in other circumstances. There is some evidence that a nasal spray of the hormone may help improve socialization among kids with autism.

For the study, Parker and her colleagues looked at the level of oxytocin present in the blood of three groups of children ages 3 to 12 including 79 kids with autism, 52 of their typically-developing siblings and 62 additional children without the developmental disorder.

Though they found that autism is not caused by a lack of oxytocin, the researchers said that the level present seems to be highly influenced by genetics, with similar levels seen in siblings even in cases where one was on the spectrum and the other was not.

The researchers cautioned that their study did not look at oxytocin levels in the cerebrospinal fluid surrounding the brain, which could be different from what was found in the blood. Nonetheless, they said their findings may help identify which individuals with autism are most likely to benefit from oxytocin-like drugs.

“Autism is so heterogeneous,” Parker said. “If we can identify biomarkers that help us identify the patients most likely to benefit from a specific therapy, we expect that will be very useful.”