Subtle signs: Parents tend to chalk up their daughters’ autism features to shyness or quietness.

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Parents of girls with autism are significantly less likely than those of affected boys to voice concerns about their child’s social behavior¹. The finding hints at another hurdle in the quest to help girls with the condition.

About one girl for every five boys receives an autism diagnosis. Clinicians identify girls with a mild form of the condition nearly two years later than boys. These girls also face a longer wait for a diagnosis after their features emerge.

Researchers have suggested that clinicians overlook the signs of autism in girls, which may be different from the ones that boys with the condition present. The new study found that parents may similarly miss the signs.

“In everyday activities with their families, [girls with autism] might not be doing things that really stick out to caregivers,” says lead investigator Lauren Little, assistant professor of occupational therapy education at the University of Kansas in Kansas City. The results appeared 18 August in Autism.

When parents overlook signs of autism in their daughters, it may have real clinical consequences: Some studies suggest that the earlier children with autism enroll in behavioral programs, the better their outcomes.

“The parents are really the ones we rely on to bring the child to the attention of the medical community,” says Rebecca Landa, director of the Center for Autism and Related Disorders at the Kennedy Krieger Institute in Baltimore, who was not involved in the study.

Social screening:

The researchers reviewed medical records from nearly 700 children who had come to the University of Kansas to be evaluated for autism or another developmental disability. They identified 63 girls who received an autism diagnosis between the ages of 1 and 12 years. They compared these girls with 63 boys who have autism, as well as 54 boys and 62 girls of similar age and intelligence with other developmental disabilities.

At the start of the diagnostic process, caregivers listed their top three concerns about their child’s behavior. Parents of boys who went on to be diagnosed with autism were about three times as likely to report worries related to social interaction as were parents of girls with autism. The parents’ concerns included worries that their child had few friendships or had difficulty getting along with peers.

“I think it is reasonable to say that fewer concerns about social impairments would decrease the likelihood of girls being referred and thus ultimately receiving a diagnosis of autism,” Little says.

It is unclear why parents did not recognize their daughters’ social difficulties. Girls may have better social skills than boys, says Rene Jamison, associate professor at the University of Kansas. A 2014 study found that girls outscore boys on a measure of friendship quality. Girls with autism have roughly the same scores as typically developing boys.

They may also be better able to mask their social quirks. A study last year found that preschool girls who go on to be diagnosed with autism tend to mirror others’ behavior during social interactions, whereas boys who are later diagnosed isolate themselves.

Probing questions:

Parents of girls may also be more likely to chalk up social difficulties to shyness or quietness, Little says.

The researchers also found that parents of girls with autism are three times less likely than those of girls with other developmental disabilities to list concerns about so-called ‘externalizing’ behaviors, such as tantrums or aggressive outbursts. Together, the findings may explain why some girls with autism are diagnosed late — or not at all.

“Their social interaction difficulties are not as pronounced as boys’,” Little says. “They’re not causing problems for their families.”

Finding more of these girls — and making sure they are diagnosed early — may require pediatricians and other clinicians to ask detailed, targeted questions. “If somebody says, ‘Well, my daughter is just really shy,’ we should ask, ‘Well, what does shy look like?’” Little says. “We might have to probe a little bit more.”