My husband and I have three brilliant, beautiful children. Three of them are boys. All three boys have Autism Spectrum Disorders. Our little girl is the youngest and is not remotely autistic.
Every day is a struggle. Though half of that is because the boys are brothers. Their disagreements do take a different form, with more screeching, but that part of the social interaction with each other is very normal.
Autism is a neuro-biological condition that falls on a spectrum of Pervasive Developmental Disorders. There are varying levels of symptoms and no two children on the the spectrum will be alike in that regard. The hallmarks of autism are impaired social interaction and speech. Sometimes symptoms are apparent from birth. Other times, as in the case of one of my boys, the child will appear normal and then begin to regress. If your child lines things up all the time, plays with or looks at things oddly (for instance looking at the wheels of a toy truck but not moving it around and making vroom sounds like most children would do), stops responding to his or her name, stops making eye contact, please have your child evaluated by a medical professional, these can be symptoms of autism. Many physicians and clinics now do routine autism screening at regular check-ups but if you have any concerns about your child be sure to speak to a doctor.
In my house we have: an 11 year old with Asperger Syndrome; a 9 year old with high-functioning autism, and a 7 year old with mild-to-moderate autism. They each have unique challenges and abilities. At the moment I must stop typing and go deal with one of the challenges.