In Re A (Children) (Conjoined Twins) [2000] 4 All ER 961 (CA), both children were certain to die in the absence of a surgical procedure to separate them. The operation would save one twin, but the parents would not give their consent. The judge observed that the parents had a legal duty to the twin that could be saved. By denying that twin the chance to live, they might be guilty of killing her under the principle in Gibbons and Proctor.