What are the genetic basis of autism? is this disorder paternal or maternal?

Both: Parents each give 50% of a child's genes so equaly likely to contribute what ever risk they have genetically. There are some specific gene abn assoc with autism. Snp-single nucleotide polymorphisms(genes that have mistake based minor abn) that result in things like enzyme dysfunction have been identified associated with autism. Most often complex and hard to pinpoint.