These criteria, Pelphrey and other researchers believe, may be missing many girls and adult women because their symptoms look different.
Historically the disorder, now estimated to affect one out of every 68 children in the U.
They, too, found that girls with the diagnosis were more likely to have low IQs and extreme behavior problems.
The girls also had fewer (or perhaps less obvious) signs of “restricted interests”—intense fixations on a particular subject such as dinosaurs or Disney films.
Scientists in recent years have investigated several explanations for autism's skewed gender ratio.
Their mom, Page, can recall how different the diagnostic process was for her two children. With Frances, she says, they went from doctor to doctor and were told to simply watch and wait—or that there were various physical reasons for her delays, such as not being able to see well because of an eye condition called strabismus that would require surgical treatment at 20 months.
“We got a lot of different random little diagnoses,” she recalls. It's not autism.’” In fact, the criteria for diagnosing autism spectrum disorder (ASD)—a developmental condition that is marked by social and communication difficulties and repetitive, inflexible patterns of behavior—are based on data derived almost entirely from studies of boys.
His interest in autism is both professional and personal.
Of his three children, only his middle child is typical.