What is the main cause for autism? what signs should i watch out for?

Autism causes: It is suspected that autism develops from a combination of a genetic predisposition which is triggered by a single or combination of unknown environmental triggers. Thousands of theories are in circulation, but to date none have been indisputably confirmed. Check out this website for screening tools you can use: http://www.firstsigns.org/screening/tools/rec.htm#asd_screens

Autism spectrum disorder (ASD): involves difficulties in social interaction, verbal and nonverbal communication and repetitive behaviors, starting with early brain development and usually emerging age 2-3. Causes appear to include genetic and environment. The following website is an excellent source of information to guide you: http://www.ninds.nih.gov/disorders/autism/detail_autism.htm.