Gender differences For the new study, Ecker and her co-authors examined whether brain anatomy differences led to a higher probability of autism in males. Specifically, they looked at cortical thickness: the depth of gray matter across the surface of the cortex. "For example, it is known from previous studies that females tend to have a thicker cortex than males in various regions of the brain," Ecker wrote in an email. Previous studies have also shown thickness to be significantly altered in people with autism. Study participants included 98 high-functioning adults with autism (49 of them men) and 98 adults without autism (51 of them men). Both groups were roughly within the same age range: mid-20s,