The criteria for an Autistic Spectrum Disorder (ASD) is the same for both boys and girls based on widely accepted diagnostic systems.
It has been widely reported that boys are four times more likely than girls to be diagnosed with ASD. There are many reasons why this disparity exists. One reason may be that parents, teachers and other adults in children’s lives may look for ASD symptoms less often in girls because of two main biases: 1) The knowledge that ASD is more likely to be diagnosed in boys, and 2) the stereotype that girls are naturally quiet.
Recent theory has also considered how boys and girls express the symptoms of ASD differently. Boys with ASD typically have great difficulty socially (e.g., poor eye contact, great difficulty making friends). Girls on the other hand, tend to put more time and energy than boys into learning social norms. For example, girls with ASD are more likely to form friendships than are boys. Because these girls seem to be socially well adjusted, their negative feelings when in social situations may be less obvious, possibly resulting in their being referred less often for ASD assessments.
Another area of interest is how social-emotional issues are expressed differently in boys and girls. Children with ASD often demonstrate social-emotional and behavioural difficulties. However, girls are more likely to internalise their distress (e.g., feeling depressed) whereas boys tend to express it more directly (e.g., disruptive behaviour). As such, boys are more likely to be referred for ASD assessments because their difficulties are more obvious.