The characteristic behaviors of autism spectrum disorder may be apparent in infancy (18 to 24 months), but they usually become clearer during early childhood (24 months to 6 years).
As part of a well-baby or well-child visit, your child’s doctor should perform a “developmental screening,” asking specific questions about your baby’s progress.The National Institute of Child Health and Human Development (NICHD) lists five behaviors that warrant further evaluation:

• Does not babble or coo by 12 months
• Does not gesture (point, wave, grasp) by 12 months
• Does not say single words by 16 months
• Does not say two-word phrases on his or her own by 24 months
• Has any loss of any language or social skill at any age

Any of these five “red flags” does not mean your child has autism. But because the disorder’s symptoms vary so widely, a child showing these behaviors should be evaluated by a multidisciplinary team. This team might include a neurologist, psychologist, developmental pediatrician, speech/language therapist, learning consultant or other professionals who are knowledgeable about autism.