[6] The issue in each claim is whether the defendant had obtained not only the plaintiffs’ written consent but the plaintiffs’ informed consent prior to the respective sterilisation procedures performed on them. [7] It is common cause that all three plaintiffs underwent a sterilisation procedure which has rendered them incapable of bearing children. [8] It was agreed between the parties that the question of liability be decided first by this Court and that the issue of quantum would stand over for adjudication at a later stage. Applicable law [9] The defendant’s defence is the defence of volenti non fit iniuria in that the plaintiffs signed consent forms which signified consent to the sterilisation procedures. [10] In Castel v De Greef 1994 (4) SA 408 (C) is regarded as a leading judgment on the issue of informed consent wherein Ackermann J (as he then was) with Friedman JP 7 and Farlam J concurring, made a paradigm shift from medical paternalism to patient autonomy. At 420A the doctrine of informed consent was placed within its common law context where the following appears: “It is important, in my view, to bear in mind that in South African law (which would seem to differ in this regard from English law) consent by a patient to medical treatment is regarded as falling under the defence of volenti fit non iniuria, which would justify an otherwise wrongful delictual act. (See, inter alia, Stoffberg v Elliot 1923 CPD 148 at 149 – 50; Lymbery v Jeffries 1925 AD 236 at 240; Lampert v Hefer NO 1955 (2) SA 507 (A) at 508; Esterhuizen’s case supra at 718 – 22; Richter’s case supra at 232 and Verhoef v Meyer 1975 (TPD) and 1976 (A) (unreported), discussed in Strauss (op cit at 35 – 6) ). It is clearly for the patient to decide whether he or she wishes to undergo the operation, in the exercise of the patient’s fundamental right to selfdetermination." [11] With reference to Rogers v Whitaker (1993) 67 ALJR 47, a decision of the High Court of Australia, the court in Castel stated the following at 426B: “Of particular importance is the conclusion of the Court in Rogers v Whitaker at 52 that: ‘The law should recognise that a doctor has a duty to warn a patient of a material risk inherent in the proposed treatment; a risk is material if, in the circumstances of the particular case, a reasonable person in the patient’s position, if warned of the risk, would be likely to attach significance to it or if the medical practitioner is or should reasonably be aware that the particular patient, if warned of the risk, would be likely to attach significance to it. This duty is subject to the therapeutic privilege.’ ”