Can you tell me how can i know a 3 year old child has asperger's syndrome?

Ask for evaluation: Ask for an evaluation from a birth to clinic. In ct these are run by the state. They do screening for autism ; other developmental delays in young children. Usually, if a child is on the spectrum, it is picked up by a nursery school teacher who would ask to speak to you about their concerns. Your pediatrician would also be someone who could help you assess what is wrong.

Social give and take: Social give and take problems: not having good eye contact to not being able to join up with peers ideas for play. Prefer to be alone/not seeking to start social interaction. This is central and it is not situational e.g like a social anxiety. Two other key areas: social communication probs and restricted patterns of behavior. Full criteria at: http://www.autismspeaks.org/what-autism/diagnosis