Is ur ‘normal’ child female? 8x more males are diagnosed with Autism then female which precludes the ‘vaccine’ argument since it would affect both sexes the same. There was a good argument about ‘plastics’ affecting the development of male fetuses here on huffy.
http://www.huffingtonpost.com/harvey-karp/cracking-the-autism-riddl_b_221202.html
Our older, “normal” child is male. Then our autistic son, and our autistic daughter. Dunno what happened between children #2 and #3.