CADS - I hope this doesn't freak you out but sometimes eye contact can be linked to autistic spectrum disorders (asd).
Of course this isn't always the case and may not apply to your son.
You really do have to look at the whole picture when seeing a child though.
I have found this link for you with red flags for asd:-
Table III. Parental Concerns that are RED FLAGS for Autism
Communication Concerns
Does not respond to his/her name
Cannot tell me what (s)he wants
Language is delayed
Doesn't follow directions
Appears deaf at times
Seems to hear sometimes but not others
Doesn't point or wave bye-bye
Used to say a few words, but now he doesn't
Social Concerns
Doesn't smile socially
Seems to prefer to play alone
Gets things for himself
Is very independent
Does things "early"
Has poor eye contact
Is in his own world
Tunes us out
Is not interested in other children
Behavioral Concerns
Tantrums
Is hyperactive/uncooperative or oppositional
Doesn't know how to play with toys
Gets stuck on things over and over
Toe walks
Has unusual attachments to toys (e.g., always is holding a certain object)
Lines things up
Is oversensitive to certain textures or sounds
Has odd movement patterns
Absolute indications for immediate further evaluation
No babbling by 12 months
No gesturing (pointing, waving bye-bye, etc) by 12 months
No single words by 16 months
No 2-word spontaneous (not just echolalic) phrases by 24 months
ANY Loss of ANY Language or Social Skills at ANY Age
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Table IV. Ask Specific Development Probes: "Does (s)he..." or
"Is there..."
Socialization
...cuddle like other children?
...look at you when you are talking or playing?
...smile in response to a smile from others?
...engage in reciprocal, back-and-forth play?
...play simple imitation games, such as pat-a-cake or peek-a-boo
...show interest in other children?
Communication
...point with his finger?
...gesture? nod yes and no?
...direct your attention by holding up objects for you to see?
...anything odd about his/her speech?
...show things to people?
...lead an adult by the hand?
...give inconsistent responses to name? ...to commands?
...use rote, repetitive, or echolalic speech?
...memorize strings of words or scripts?
Behavior
...have repetitive, stereotyped, or odd motor behavior?
...have preoccupations or a narrow range of interests?
...attend more to parts of objects (e.g., wheels)?
...have limited or absent pretend play?
...imitate other people's actions?
...play with toys in the same exact way each time?
...strongly attached to a specific unusual object(s)?