Why are boys diagnosed with autism more often than girls?

According to the latest numbers from the Centers for Disease Control, boys outnumber girls nearly four to one with respect to autism diagnoses. But does that mean there are actually more boys than girls with autism? Research tells us another story: many girls with autism are often misunderstood, misdiagnosed, or undiagnosed.

Girls with autism may be harder to diagnose for many reasons, including stereotypes around what autism “should” look like (most diagnostic criteria are developed around boys); the relationship girls have with their autism and how they cope with, mask, and compensate for their symptoms; social and cultural factors; and even biology.

In one study, researchers found that girls with an autism diagnosis have more difficulties in social communication than boys with the diagnosis, also suggesting that girls may be more likely to be diagnosed only if they have significant social challenges. Another study on sex differences in autism found that the traits required for an autism diagnosis tend to differ for girls and boys, resulting perhaps in the diagnosis bias. For example, girls are less likely than boys to be diagnosed with autism even when parents report high levels of repetitive and restricted behavior symptoms. However, the probability of diagnosis increased in girls when parents reported high levels of emotional and behavioral challenges.

For much more on this topic, see our article Autism in Girls.