In a significant victory for parents of children with autism, a federal judge has certified a class action suit against Cigna Corp. for refusing to cover two types of behavioral treatments on the grounds that they are “investigative or experimental.”

But U.S. District Court Judge Juan R. Sanchez ruled that the class must be limited to parents who filed claims for the treatment and were denied. He refused to expand the class to include those who may have considered it futile to file a claim because of Cigna’s alleged blanket policy.