Differences in Diagnosing Autism in Girls and Boys

Recent research suggests that autism spectrum disorder (ASD) may look quite different in girls—so different, in fact, that it can be difficult to use existing autism diagnostic criteria. This is because most early studies of autistic children were focused on boys, but there may be other reasons.

A diagnosis is often missed in autistic girls and women. This may occur because they have fewer intense autism traits (like intellectual disability) than boys. Or, girls may be better at masking (hiding) their autism traits. A missed diagnosis means delayed intervention that can affect a lifetime, and the potential for co-occurring conditions like anxiety.

This article will discuss the differences between female children with autism vs. male children with autism. It refers to boys and girls on the basis of their assigned sex at birth, while acknowledging that there is significant gender identity variation among autistic people (but no clear consensus on the link).

Is Autism More Common in Boys vs. Girls?

An autism diagnosis is far more common in boys; it's four times as likely, and researchers continue to work to understand why. Some of the possible reasons include:

• Familial patterns and genetic links that may be "protective" in girls
• Hormonal effects (like fetal testosterone levels) attributed to sex differences

Studies suggest there really is a higher incidence of autism in males, but the ratio is closer to three-to-one because so many autism diagnoses are "camouflaged" and therefore missed in girls.

Some of the reasons that autism traits may be missed or misidentified in girls include:

• Changes in how autism is diagnosed, with more subtle autism traits now included
• Testing for how autism is assessed that has an inherent bias for patterns in boys
• Sex differences in how autism traits are expressed (language skills, for example)
• Social pressures and gendered expectations for girls' behavior that mask autism traits
• Girls' ability to mask their own autism traits, which may be stronger than it is in boys

Some study authors note that their results are based on assigned sex at birth, but it's known that there are greater sex and gender identity variations (and gender dysphoria) among autistic people.

How Autistic Girls Differ From Autistic Boys

There's some evidence to suggest progress in how girls are diagnosed with autism. A study of 2,684 people in nine European nations looked at sex, age, and other factors when assessing results of common autism diagnostic tests: the Autism Diagnostic Interview-Revised (ADI-R), the Autism Diagnostic Observation Schedule (ADOS), or both.

At ages 4 to 5, considered the most common diagnostic window by the researchers, girls less often showed stereotyped autism traits. However, they had similar challenges with social cues when tested, even though these may not emerge in day-to-day social settings. More research is needed, but the study suggests awareness of these potential sex differences when screening for autism can help.

Social Skills and Play

It's common for different play styles to emerge among neurotypically developing boys and girls. These differences can make an autism diagnosis more obvious in boys, as was the case in a study of 96 children: 24 autistic boys, 24 autistic girls, and their corresponding neurotypical peers.

Autistic boys play alone, so it's visible to others when they're not participating in organized games with other boys. Autistic girls find it easier to "blend" among their friends and camouflage their autism traits because the social framework allows them to stay closer to the support of friends.

An autistic girl's mentors, though, may drift off as they enter adolescence and find other interests or groups of friends. Autistic girls who rely on masking may find it harder to do so with the increasing social and relationship demands of adolescence and adulthood, leading to the later diagnosis.

Boys also show the autism trait of highly focused and repetitive behaviors more than girls do. Girls do have perseverative interests (fixated on one topic, such as TV stars or music), but these are likely to appear more neurotypical than a boy's intense focus on train schedules or baseball statistics.

Social Communication and Language

While boys' social communication issues become challenging very early in their lives, girls may be able to manage the social demands of early childhood but run into difficulties as they enter early adolescence.

Autistic boys may tend to engage in disruptive behavior to gain objects, while autistic girls may tend to engage in disruptive behavior to get attention. Autistic girls are less likely to behave confrontationally or intensely and more likely to be passive or withdrawn, but they may be more prone to co-occurring disorders like anxiety and depression.

Summary

Both boys and girls are diagnosed with autism, though it's more common in boys. Some studies have identified underlying reasons for why there's a higher incidence of an autism diagnosis in boys, but genetic and sex differences don't fully account for the lower rate of diagnosis in girls.

Other studies point to cultural biases, including the ways that tests are used to diagnose autism. They've estimated the degree to which autism in girls is missed or misdiagnosed, and called for increased awareness to ensure that women and girls are accurately diagnosed and treated.