Erin Lopes gives a saliva sample for the Autism Sisters Project, which is building a database to help scientists look for genetic clues and protective factors. Her son, Tommy, was diagnosed with autism at age 3. Her daughter, Evee does not have the condition. Photo: AP Photo/Seth Wenig
 
Think autism and an image of an awkward boy typically emerges, but the way autism strikes girls?or doesn?t?may help reveal some of the developmental disorder?s frustrating secrets.
Autism is at least four times more common in boys, but scientists taking a closer look are finding some gender-based surprises: Many girls with autism have social skills that can mask the condition. And some girls do not show symptoms of autism even when they have the same genetic mutations seen in boys with the condition. ?Autism may not be the same thing in boys and girls,? said Kevin Pelphrey, an autism researcher at George Washington University.
The causes of autism aren?t known. Genetic mutations are thought to play a role, and outside factors including older parents and premature birth also have been implicated. But the gender effect is now a hot topic in autism research and one that could lead to new ways of diagnosing and treating a condition that affects at least 1 in 68 Canadian children.
What science shows

Brain imaging suggests there may be an additional explanation for why many girls with autism have more subtle symptoms than boys, Pelphrey said. Even in girls who clearly have autism, he said, ...