What are the Signs of Autism?

According to First Signs, the top "red flags" to look for are:

• no big smiles or other warm, joyful expressions by 6 months 
• no back and forth sharing of sounds, smiles, or other facial expressions by 9 months
• no babbling by 12 months
• no back and forth gestures, such as pointing, showing, reaching, or waving by 12 months
• no words by 16 months
• no 2 word meaningful phrases (without imitating or repeating) by 24 months
• any loss of speech or babbling or social skills at any age

In addition, the Mayo Clinic suggests looking for the following signs:

Social Skills

• Fails to respond to name
• Poor eye contact
• Appears not to hear
• Resists cuddling and holding
• Appears unaware of others feelings
• Seems to prefer playing alone--retreats into their "own world"

Language Skills

• Starts talking later than other children
• Loses previously acquired abilities
• speaks with an abnormal tone or rhythm
• Can't start or maintain conversation
• Repeats words or phrases verbatim, but doesn't understand how to use them

Behavior

• Performs repetitive movements, such as rocking or spinning
• Develops specific routines and rituals
• Becomes disturbed at the slightest change in routines and rituals
• May be unusually sensitive to light, sound, and touch
• Moves constantly
• Fascinated by parts of an object, such as spinning wheels on a car

I recommend checking out the Autism Speaks website. You have to register to watch them, but the Video Glossary is an excellent resource because it shows videos of children with autism right next to typically developing children.

Of course, all children exhibit differences in development and personality so don't panic if your child likes routine or speaks later than others. If you see a large combination of these signs, especially the First Signs list, I would suggest taking your child to the doctor.