Are There Really More Autistic Boys Than Girls?

Updated July 19, 2015. By Lisa Jo Rudy  Autism Spectrum Disorders Expert 

Read any source on autism, and you'll learn that boys and men with the diagnosis outnumber girls and women by a factor of at least 4:1. The gender gap increases with higher functioning individuals (those who would, in the past, have been diagnosed with Asperger syndrome) to something like 11:1.

The idea that autism is a "male disorder" has become so well-established that some researchers (particularly Simon Baron-Cohen) have described autism as the manifestation of an "extreme male brain." Baron-Cohen points to traits such as apparent lack of empathy, focus on details and ordering, talents in the areas of math and science, and a preference for routine, saying that these are all manifestations of "maleness," and are also very common in autism.

Baron-Cohen and his colleagues have taken this idea to the lab, where they have explored the idea that more testosterone in the womb is likely to lead to autism. Just a little extra testosterone, he hypothesized, could be enough to push boys into autism. Some of their research suggests the possibility that this idea could hold water.
At the same time, however, other researchers have explored the question of whether autism may simply be under-diagnosed in girls. They, too, are finding some intriguing results.

At the Kennedy Krieger Institute in Baltimore, for example, researchers are finding that girls with autism are more likely to slip under the radar because they think and behave differently from boys with the disorder:
Girls struggled more with the ability to recognize social cues and interact with others. They had trouble interpreting requests made of them, took things too literally, struggled to understand jokes and couldn't read into people's tone of voice or facial expressions...

On the other hand, boys exhibited much more physical symptoms. They engaged in repetitive behaviors, like turning the wheel of a toy around and around for extended periods, as well as unusual mannerisms such as flapping their hands..

In addition, boys with autism often express fascinations with topics considered "odd" by the general population (e.g., memorizing timetables or lists of statistics) while girls with autism seem to have fairly gender-appropriate fascinations which must be examined closely in order to appear "autistic." For example, a girl with autism might express a fascination with a pop star, pin up his posters, and know everything about his daily routine  -- which appears "normal" to most parents -- but know little or nothing about his music.

Girls with autism also appear to be less likely to act out and more likely to find adaptive behaviors that allow them to function at least semi-successfully in typical settings. For example, rather than showing aggressive or hyperactive behavior (which, of course, is noticed even in preschoolers) girls with autism may withdraw, become passive, or even become depressed. 

Quiet, "shy," or passive girls are culturally acceptable, and quiet girls are rarely picked out as problem children -- especially if they have a relatively high IQ and are capable of functioning in a school setting. As a result, girls on the spectrum may not be identified as such until they reach their teen years and are completely unable to manage the complex social expectations surrounding sexuality, flirting, and romance.
It seems very likely that the number of girls with autism will appear to rise in the next few years as more girls are identified with the disorder. The question of whether those girls were always there, however, may remain open.

Sources:
Baron-Cohen S¹.The extreme male brain theory of autism. Trends Cogn Sci. 2002 Jun 1;6(6):248-254.
DeWeerdt, S. Autism characteristics differ by gender, studies find. Simons Foundation, 27 March 2014.
Dworzynski K. et al. J. Am. Acad. Child Adolesc. Psychiatry 51, 788-797 (2012)
Sarris, M. Not Just for Boys: When Autism Spectrum Disorders Affect Girls. Interactive Autism Network at Kennedy Krieger Institute, February 19, 2013.

8 Differences Between Boys and Girls with Autism

Updated July 22, 2015. By Lisa Jo Rudy  Autism Spectrum Disorders Expert 

 The diagnostic criteria for autism doesn't discriminate between boys and girls or between men and women. But recent research findings suggest that autism may look quite different in girls--so different, in fact, that it can be difficult to diagnose. One researcher at the Kennedy Krieger Interactive Autism Network raised this question in a report on Girl's with ASD: Researchers looking at differences between boys and girls with ASD have often not found much difference. Is this because there is no difference, or because only girls with ASD who most resemble boys with ASD are diagnosed and therefore included in studies?

One difficulty that researchers experience is that girls with autism seem to behave in ways that are considered acceptable -- if not ideal -- for girls as opposed to boys. For example, girls with autism may appear to be passive, withdrawn, dependent on others, uninvolved, or even depressed (just as boys do). They may become passionately and even obsessively interested in very specific areas (just as boys do), but they may not gravitate toward the "geeky" areas of technology or math. Sadly, in western culture, girls who exhibit these behaviors are more likely to be ignored or bullied than diagnosed and treated.
With all those caveats, however, research is moving forward, and providing us with more clues to ASD in girls. 


Based on recent research, here are a few of the ways in which girls with autism appear to differ from boys with autism:

1. Boys with autism tend to have very repetitive and limited areas of play. Girls with autism are less repetitive and have broader areas of play.
2. Girls with autism are more likely than boys to be able to respond to non-verbal communication such as pointing or gaze following. They are also somewhat more focused and less prone to distraction.
3. 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.
4. According to the Kennedy Krieger report, Boys with ASD may tend to engage in disruptive behavior to gain objects, while girls with ASD may tend to engage in disruptive behavior to get attention.
5. Girls with autism are more likely than boys to also suffer from anxiety and/or depression.
6. While girls with autism do have perseverative interests, they are more likely to choose interests (such as TV stars or music) that appear more typical than, for example, many boys' perseverative interests in schedules, statistics, or transportation.
7. Girls with autism are less likely to behave aggressively, and more likely to be passive or withdrawn.
8. It is fairly common for girls with autism to appear socially competent as youngsters because they are "taken under the wings" of other girls who enjoy mentoring their peers. These mentors often fade out of the picture as they enter adolescence and find other interests or groups of friends.

Sources:
DeWeerdt, S. Autism characteristics differ by gender, studies find. Simons Foundation, 27 March 2014.
Dworzynski K. et al. J. Am. Acad. Child Adolesc. Psychiatry 51, 788-797 (2012)
Nichols, Shana. A Girl's-Eye View: Detecting and Understanding Autism Spectrum Disorders in Females. Interactive Autism Network at Kennedy Krieger Institute, December 2009.
Sarris, M. Not Just for Boys: When Autism Spectrum Disorders Affect Girls. Interactive Autism Network at Kennedy Krieger Institute, February 19, 2013.