What age does Autism appear? Autism spectrum disorder can be associated with a genetic disorder and in another children's genetic change mutations may increase the risk of Autism spectrum disorder . Harmon abnormalities in pregnant women are as a significant potential risk factor for autism "offspring " and that sex Harmon's may be a part of the autism. Many children's shows symptoms of Autism at the age of 6 months age are earlier, some early signs of Autism are problems with eye contacts. Many children's shows the symptoms of Autism at the age of 2 to 3 year's of age. And the signs of Autism are problems are social interaction and social behavior. Begin before the age of two or three years many child's symptoms of autism are visible even after the age of six months when the child is called by his name but he is not responding no smile does not respond to loud noises does not do activities according to his age then you should consult a doctor as soon as possible.