You don't have to have autism, but you can still have personality and brain traits that are more characteristic of people that are diagnosed as autistic.

The question shouldn't be "Do you have autism?" but "How autistic are you?". The DSM-V's elimination of Asperger's Syndrome as something seperate from autism makes it clearer than ever that autism is a continuous spectrum. It is also obvious to me that ADHD is a spectrum, though the DSM doesn't quite agree with me on that point.