Is it true that a child that does not point must be autistic?

No, not true: A child who is growing fine, developing skills on time, interacting with other people, emotionally nice to be with, and smiles happily is likely normal. Such a child may point or not point, but it shouldn't matter, as the rest of his life looks normal. However, if a child has several odd traits or behaviors, and one of those behaviors is "not pointing", then he might (not must) be autistic.

Not always: When evaluating children for autism, there are a few symptoms that toddlers may or may not exhibit, pointing is a clue, making eye contact and observing the child for approval from parent when they do point, are all helpful when considering a diagnosis of autism. Talk with your child's doctor if you have concerns. Most of what I have discussed here are signs that are helpful at 18-24 month range.

A Sign: Lack of pointing in a toddler is a sign, taken with other symptoms of potential problems.But dr kwok's response is basically correct.