Opinion Conversations on the science of autism research.

Autism’s gender bias evident before diagnosis

by  /  13 March 2015

BlueOrange Studio/Shutterstock.com Shell game: Girls with autism show subtle repetitive behaviors, such as creating collections of objects.

One of the most consistent findings in autism — and arguably the most perplexing — is that it affects four times as many boys as girls. There’s no shortage of theories to explain this gender imbalance: Autism-related behaviors manifest differently in girls, who also require more mutations than boys do to trigger the disorder.

Many studies have investigated behavioral differences between boys and girls after diagnosis. But these behaviors may not be the same as those that precede diagnosis — or the same ones that make autism more difficult to identify in girls. Also, the standard diagnostic tests are thought to be better at picking up autism-related behaviors in boys than in girls.

A new study, published 25 February in Autism, looks at these much-neglected prediagnostic behaviors. It asks parents or other caregivers to recall their child’s behavior before diagnosis and identifies clear differences in social and repetitive behaviors between boys and girls. For example, girls are more motivated to fit in so they develop skills to make it look like they do.

The researchers askedthe caregivers of 92 boys and 60 girls with autism to complete an online survey with 17 multiple-choice questions about the children’s behaviors. They also asked caregivers to recall how clinicians responded when they first voiced concerns about their child, and whether any teachers sounded alarms about the child’s development. All of the children were diagnosed at about age 9.

Girls later diagnosed with autism tend to have better vocabularies than boys and are more adept at imitating others’ actions, the survey found. Girls also have a stronger desire to fit in with peers. The caregivers also indicated that girls often cope during social situations by mimicking others, whereas boys tend to walk away or observe quietly.

Taken together, the findings jibe with previous studies that have suggested that the social behaviors of girls mask their atypical development.

The survey also probed early differences in repetitive behaviors and restricted interests, a core feature of autism. Previous studies have reported that girls show fewer repetitive behaviors than boys do, but the survey revealed that only the nature of the interests differs with gender.

Boys tend to fixate on wheeled toys — obsessively lining them up or spinning the wheels; girls, on the other hand, tend to collect seemingly random objects, such as shells, feathers and stickers. Keeping such collections may more closely resemble typical development than does a fascination with wheeled toys, which is often associated with autism, and so is less likely to be picked up as a sign of the disorder.

Although clinicians responded similarly to caregiver concerns about boys and girls, teachers were more likely to report concerns about boys. This finding suggests that girls’ symptoms manifest differently at school than at home. Conflicting accounts of a child’s behavior from caregiver and teacher may make it all the more difficult for a clinician to diagnose the disorder in girls.

The study is not without limitations, as a child’s current symptoms may skew a caregiver’s recollection of past behaviors. Still, information about early sex differences may yield valuable clues to help diagnose the disorder in girls.

4 responses to “Autism’s gender bias evident before diagnosis”

  1. Morwenna Stewart says:

    NO NO NO. Women are not affected in smaller numbers. They are diagnosed in smaller numbers. Why can no one seem to grasp this? The bias is in referral and diagnostic criteria. The article is about gender differences, not gender bias itself.

  2. Amy Oconnell says:

    My newly 4yo daughter has severe autism. I do believe that females are less likely to have autism, not that it’s a problem work diagnoses. We live blocks from Kennedy Krieger’s Center for Autism and Engaged Disorders and they work primarily with children. Any patent w a child like mine,male or female, would have the child assessed. I’m sure the stats will change in a multitude of ways over the next 5, 10 and more yrs and perhaps the gender gap will lessen as times change but that will likely come with more research. My question is, my 2yo has a speech delay and emulates certain characteristics of my autistic daughter. He’s spent 2yrs w her. But he LOVES cars and trucks and wheeling them around (as well as ccoloring, playing hide and seek, etc… He’s very different than her). But he does gravitate toward anything with wheels. I just thought it was a boy thing. I have him in speech therapy. Should I be concerned that perhaps he could be on the spectrum? I’ve always know my daughter was different. My son, not at all! So this study is a big surprise for my family. Thanks!

  3. Amy O'Connell says:

    PS. Please excuse my typos above… wanted to add that I def disagree with the comment before mine. Asst least here in Baltimore. My 4yo attends a KKI autism specific prek-8th grade school and the male female ratio is pretty much that of the 75/25% avg. I know the IEP system here is strong and solid as I’ve been through it personally. They care about every child and ensure each child, regardless of gender, socio-economic level, insurance or lack thereof,etc., has every assessment necessary and is treated kindly and like a real human being. I’m not sure what happened befor my daughter’s and the kids at her school’s time but I can confidently say that as of today, the outlook here is bright. Maybe I’m just blessed to be in the Johns Hopkins/ Kennedy Krieger HQ, IDK. I like to think more positively than that. SFARI: Great work as always. Thank you for all you do!

  4. Brenda Robinson says:

    I would collect objects have repetitive play rituals find it hard and still do to make close friends disregarded anything that I didn’t find interesting. And even now tend to mimic other around me when in unfamiliar situations. I do have a form of dyslexia but still struggle with normal learning. I do believe that autism does present differently in females and yes the nature of mimicking and passive behaviour does fool. But now that so much more is expected of children and less diversity is aloud these girls are just see as a problem. The unusual mind set is not nurtured in the educational system.

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