One of the challenges with this style of study is that it is difficult to account for every aspect of life which might affect the probability of developing autism, such as family history.

BBC: Autism: Traffic pollution linked, study suggests

She's with the University of Texas and she did a study saying that style of parenting isn't really very effective and that those kids actually do worse academically and socially than kids whose parents give them more of a loving approach, as it were.

NPR: Listener Encourages Hugs And Violins