Link To Obese Mothers And Autism?

I was going to post a picture on this, but thought better of it.

http://vitals.msnbc.msn.com/_news/2012/04/09/11061081-obese-moms-may-be-more-likely-to-have-autistic-child-study-suggests?lite

I am not so sure this proves a relation to Autism, or just substantiates Americans are generally fat.