Women with silicone breast implants who voted against a $3.2-billion settlement plan offered by Dow Corning Corp. are now free to sue its corporate parents, a federal judge has ruled. If upheld, the ruling could unravel the complicated deal aimed at ending years of legal battles over claims that silicone implants caused illnesses in hundreds of thousands of women around the world. U.S. Bankruptcy Judge Arthur Spector in Michigan ruled late Tuesday that any woman who voted against the settlement approved last month could sue Dow Corning's corporate parents, Dow Chemical Co. and Corning Corp., each of which owns half of Dow Corning. The settlement barred further lawsuits against Dow Chemical and Corning Corp. over silicone implants. The clause is one of the keys to the settlement, part of a $4.5-billion bankruptcy reorganization plan for Dow Corning. Dow Corning will appeal the opinion, Dow Corning spokesman Michael Jackson said.