Ignorant Title
The title suggests that no single cause exists. This is not supported by the story, it's sources or the research. It is still unknown. There are risk factors which are correlated, but no cause is determined. For all we know crickets song could be the cause.
Just look at the titles of the source stories. "Risk factors for autism remain elusive: study" — Reuters, July 11, 2011 "Search for Autism Cause Yields Many Suspects" — MedPage Today, July, 11, 2011 "Birth Complications Linked to Autism" — WebMD, July, 11, 2011 "Fetal and Birth-Related Complications May Be Linked to Autism"
Instead of letting the results of the study show, let's just let journalists pick and choose what they think the research means. All these titles lean in different directions some of them are just plain wrong. I won't go through all of them because this is the Wikinews article.
The research did not conclude that there is no single cause of Autism. No conclusion like that at all.