http://www.webmd.com/brain/autism/autism-symptoms
How old is your son? Has he been screened? There are many different symptoms of autism and you do not have to display every single one to be diagnosed with it. For example many people with autism have poor eye contact, struggle with speech and communication, stim (ie flap hands, toe walk), do not get dizzy, have trouble with some motor movements. The list goes on. Every person with autism is different and has their own personality. It is an interesting condition because of this. It is incorrect to say "always" or "never." One of the things that confused me before my daughter got her diagnosis was her kindness and affection. I believed the MYTH that people with autism cannot have interpersonal relationships and are super distant. This is completely untrue. Once I realized this I knew she had autism. Good luck!