I do not have Autism, but looking at my brother I feel that we sometimes have similar characteristics. I am sensitive to overstimulation. I get frustrated easily when too many things are going on. I become irritable and tend to feel restless in these situations. I often have difficulty identifying my feelings. Hence, I have some characteristics of Autism. Why is it that my brother is diagnosed with the disorder and I am not? 

    It may not even be a question of whether my brother got certain alleles of genes that I didn’t get. It may just be that boys are more at risk for autism diagnosis than girls are. In several studies, including one by psychiatrist Leo Kanner, it was found that boys were four times more likely to show autistic symptoms than girls were. ASD research over the years has shown that between four and five times as many boys as girls are diagnosed with autism annually. This phenomenon has gone back even since autism was initially discovered. The exact reasons for the skewed sex ratio are still unknown. Many scientists have noticed that there is something male-related when observing the way individuals with autism think, act, etc. Hans Asperger claimed that the observations and descriptions of his patients could potentially represent an “extreme variant of male intelligence” (Foden. et. al). An autism researcher at Cambridge University, Simon Baron-Cohen, proposed the extreme male brain theory of autism, which tries to explain the similarities between traits of the masculine human and traits associated with autism. For example, men show strengths in math and reasoning, however when compared with females, males are at higher risk for language impairment and difficulties with cooperation and social-judgement tasks. A study conducted by Nicola Grissom, a researcher at the University of Minnesota, focused on the usage of mouse models that resembled symptoms of autism. In these mice, Grissom mirrored autistic individuals where one copy of a chromosome lacked a specific region of DNA. The results showed that female mice with the mutated chromosome learned new behaviors just as quickly as neurotypical female mice. However, male mice with the mutated chromosome had a hard time learning new behaviors and rather performed old behaviors repetitively. 

Overall, autism diagnosis is often overlooked in girls. Guardians and adults in children’s lives usually think of autism as a disorder that affects mainly boys. This isn’t necessarily the case. It doesn’t not occur in girls, it just is more difficult to diagnose in girls than in boys. Girls have less repetitive behaviors than boys do and most likely are better at hiding their autism characteristics by resembling the people around them. However, detection of autism in girls has gotten better over the years. In 1995, a Danish study found the sex ratio for autism to be about 8 to 1. By 2010, that ratio dropped to 3 to 1.