I believe autism and ADHD are related. My girlfriend is majoring in phsycology to study their inherent differences, (also alcoholism). Anywas, Autism seems to be a little extreme. I have ADHD, as well as my uncle. His son has autism. You usually know by about age two. He is now nine years old and has never talked, my uncle has spent over three million dollars in autistic education and research at the University of Washington. He'd be lucky to be able to put sentences together or even learn addition with autism. There are cases that aren't as bad, but I surely think you would have known for sure a lot sooner. Hopefully this lightens things up for you?
Paul