You have only thinking like that but you're not sure. In fact, if you'd make a complete checkup of him the doctor would automatically diagnose the problem.
Why do you WANT the diagnosis of autism? There may be other underlying causes with similar signs. Find a neuropsychologist and get your child tested. Autism is lifelong, why GET the doctor to give the diagnosis when there may be another cause. Good luck
Do not go to a regular docter but to a neuropsychologist and explain the creasons of your ways.
My 11 year old son has Asperger Syndrome. He has always been very social, too social in fact. He tends to invade other people's space and used to hug total strangers. He talks to everyone, though he does tend to not respond to his friends from school greeting him when we're in public.