Autism is a condition that causes people to act differently from neurotypical people. It's often called "autism," but it's not really an illness; it's just a different kind of behavior than most people exhibit.
It used to be divided into subtypes, such as Aspergers'syndromes, but it's now considered a disorder with a broad range of varying degrees of symptomatology and severities.
But among adults, autism is about four and a half times more common in males than in females.