1) Does the baby respond to his or her name when called by the caregiver? Typical babies are very responsive to the voices of familiar people, and often respond with smiles and looks within the first few months of life. They also respond to their own name by looking to the person who called them
2) Does the young child engage in “joint attention”?  Typical towards the end of their first year, infants begin to shift their gaze from toys to people, follow other’s points, monitor the gaze of others, point to objects or events to share interest, and show toys to others.
3) Does the child imitate others? Typical infants can imitate body and facial movements. Another way an infant imitates is with common infant games such as pat-a-cake.
4) Does the child respond emotionally to others? Typical infants are aware of the emotions of others, They smile when others smile at them, or if an infants observe another child crying, they may cry themselves, or looked concerned.
5) Does the baby engage in pretend play? Typically pretend play doesn’t begin until the end of the first year. Their first actions may involve pretending to feed themselves, their mother or a doll, brush the doll’s hair, or wipe the doll’s nose.

There are some very useful checklists as well as growth and development tables available at http://www.cdc.gov/ncbddd/autism/ActEarly/ccp/downloadmaterials.html for children of all ages. These milestones do not apply to just autism.

You should look to see if your infant is not meeting any of these normal milestones.  It is important to remember, however, that all children and infants develop at a different pace. Just because your infant does not reach a certain milestone on the normal cycle does not mean your child has autism or any other condition, it just might mean you should consult your physician.

Below are some of the red flags you should watch for in your infant to make sure he or she is developing at the right pace. If any of the following occur, it is a good idea to seek advice from your pediatrician or family physician:

By 18 Months of Age:

•     Does not search for objects that are hidden while he or she watches
•     Says no single words (“mama” or “dada”)
•     Does not learn to use gestures, such as waving or shaking head
•     Does not point to objects or pictures
•     Experiences a dramatic loss of skills he or she once had

By 24 Months of Age:

•     Cannot walk by 18 months
•     Fails to develop a mature heel-toe walking pattern after several months of walking, or walks only on his toes Does not speak at least 15 words
•     Does not use two-word sentences by age 2
•     By 15 months, does not seem to know the function of common household objects (brush, telephone, bell, fork, spoon)
•     Does not imitate actions or words by the end of this period
•     Does not follow simple instructions by age 2
•     Cannot push a wheeled toy by age 2
•     Experiences a dramatic loss of skills he or she once had