My 1st son is mildly autistic and now i am pregnant will there be any chance of 2nd child might be autistic?

Possible : Depending on the cause of your first child's diagnosis your second child may be affected. Since most children do not have chromosomal defects screening cannot provide reassurance. There are more subtle epigenetic abnormalities that can be seen and some can be addressed after birth. You would need to have your first child seen by a provider to assist in evaluation process.

A prospective study: Of younger siblings of children with autism by the mind institute revealed that each sibling of a child with autistic spectrum disorder has a 1/5 chance of having asd. Another study showed 30% of siblings had early signs of asd: of these, some had language impairment instead. If a genetic cause is found on microarray (cgh). Or dna probe for fragile x , risk depends on the pattern of inheritance.