Why is pointing and waving an indication of autism.?

my son hardly points or waves, and I know he's not autistic. He does everything else, and understands simply instructions. There are so many kids who do not point or wave by the time they are 12 months and are fine. I really thing they should reconsider they as an indicator. They should take into account that some parents don't point or wave to their kids, so why should they be expected of these kids. What are your thoughts? Did your kids point or wave by the time they were 12 months?