 Justice Potter Stewart wrote a concurring opinion in which he stated that even though the Constitution makes no mention of the right to choose to have an abortion without interference, he thought the Court's decision was a permissible interpretation of the doctrine of substantive due process, which says that the Due Process Clause protection of liberty extends beyond simple procedures and protects certain fundamental rights.Justice William O. Douglas wrote a concurring opinion in which he described how he believed that while the Court was correct to find that the right to choose to have an abortion was a fundamental right, it would be better to derive it from the Ninth Amendmentwhich states that the fact that a right is not specifically enumerated in the Constitution shall not be construed to mean that American people do not possess itrather than through the Fourteenth Amendment's Due Process Clause.Chief Justice Warren Burger wrote a concurrence in which he wrote that he thought it would be permissible to allow a state to require two physicians to certify an abortion before it could be performed.