Like Miss Algernon said in a sense the experiment has already been done via twin studies.
Trouble is the twin studies to date point in different directions. A California study in 2011 of 192 twins pointed to environment. A later bigger study done by Dr. Frazier using a nationwide data base analying 562 sets of both identical, and fraternal twins pointed to genes being the biggest factor. Its on a website by Interactive Autism Network (Im not good at posting links).
My guess is that autism is mostly genetic, or epigenetic. If they cloned you then your clone would also be autistic.
"environment" in the sense of what kind of family and what kind of parenting you get wouldnt effect it much. Environment in the larger sense of things like: pollution in your drinking water, polluting chemicals in the air, the age your parents were when you were conceived, or when your mom carried you, might have more effect. But they might effect you via effecting which of your genes get turned on, and off. Its a hard thing to unravel.