On Saturday I took my son to a Triple-A baseball game in Norfolk. We were already seated when a man and his son came and sat next two us. In about three seconds this happened: he looked at my son, I looked at his son, and we both looked at each other and said, without words, Yes, my son is autistic.
Of course it wasn't long very long until everyone around us figured there was something different about our sons. But it was amazing the way we made the diagnosis, instantly, before either son had displayed any overt characteristic behavior.
I wonder if anyone has studied the speed and accuracy with which a parent can diagnose autism, compared to a trained psychologist.