Autism: Why is it so Much More Common in Boys?

As data from the CDC has come in, the rise in rates of autism is alarming, especially in boys. Now, the incidence of autism is 1 in 88, but in boys it is a staggering 1 in 54. I, and probably many other people are baffled by this data, so I would like to explore why it is so much more common for boys to be diagnosed with autism than girls.

First, it is important to really understand what autism is. According to Autism Speaks, autism is "Characterized, in varying degrees, by difficulties in social interaction, verbal and nonverbal communication and repetitive behaviors".  Autism is a spectrum disorder, meaning it can range from people having trouble understanding social cues, all the way to people unable to talk and barely able to communicate basic necessities. 

Now, one reason that there is such a large gap between boys with autism and girls with autism, is there is different symptoms displayed by each sex. According to an article in CNN, one hypothesis is "That perhaps higher-functioning girls with autism are missed by clinicians who are not experts in diagnosis. [Also] girls have better social skills than higher-functioning boys with autism and so are not diagnosed as readily". Because of the difference in symptoms shown by the child, the girls are not as commonly diagnosed because of their ability to have better social skills. Also CNN reports that since girls don't engage in as many repetitive behaviors as boys, like rocking or spinning (a hallmark symptom of autism), so the lack of that symptom could be deceive to inexperienced clinicians. 

Do you think there are actually more boys with autism than girls, or are girls being misdiagnosed?