OPINION
HENDLEY, Judge.This medical malpractice case is before us for the second time. In our original decision, Demers v. Gerety, 85 N.M. 641, 515 P.2d 645 (Ct.App.1973), we affirmed, holding, among other things, that since the trial court correctly denied directed verdict and judgment n. o. v. motions as to one of plaintiffs theories — lack of consent to the operation — we did not need to decide whether he was also correct as to plaintiff’s other theories. Our Supreme Court in Gerety v. Demers, 86 N.M. 141, 520 P. 2d 869 (1974), reversed on procedural grounds as to this point, holding that § 21-1-1 (50) (b), N.M.S.A.1953 (Repl. Vol. 4, 1970) requires that we must decide the propriety of the trial court’s ruling as to plaintiff’s other two theories: (1) Negligent Surgery; and, (2) Lack of Informed Consent.
We will not repeat the facts stated in Demers v. Gerety, (Ct.App.), supra.
Negligent Surgery
On November 13, 1967 defendant Gerety surgically revised plaintiff’s ileostomy (small intestine outlet through the abdominal wall). Plaintiff alleged the surgery was negligently performed. His theory concerns the proper length of the stoma protruding from plaintiff’s abdomen. He claimed the proper length was approximately one and one-half to two centimeters and that his was flush to the skin. Even assuming there was conflicting evidence on the duty of care — the proper stoma length —and the breach of that duty, there was no evidence that the alleged failure of defendant to make a long enough stoma caused plaintiff’s damages.
Damages consisted of the costs, pain and disability suffered by plaintiff by reason of two subsequent operations on his ileostomy. The uncontradicted evidence on the record establishes that the two operations were performed to cure an abscess (a collection of purulent material, like a boil) on the bowel wall that had produced a bowel obstruction. Uncontradicted evidence also established that the abscess was caused by necrosis (the dying of skin by loss of blood supply) of the ileostomy stoma that allowed bacteria to enter the bowel wall. There is no medical evidence that the necrosis was caused by the alleged shortness of the stoma. Cervantes v. For-bis, 73 N.M. 445, 389 P.2d 210 (1964). Lay testimony under the facts of this case will not suffice. See Mascarenas v. Gonzales, 83 N.M. 749, 497 P.2d 751 (Ct.App. 1972). Since there was no expert testimony, there was no issue as to causation and the trial court incorrectly denied defendant’s motion to direct a verdict on the issue of negligent surgery. We must therefore reverse. Gerety v. Demers, (Sup.Ct.), supra; Reed v. Styron, 69 N.M. 262, 365 P.2d 912 (1961).
Lack of Informed Consent
Since our prior opinion decided there was a lack of consent, it goes without saying, there could not have been any informed consent.
Cross-Appeal
Plaintiff raises a valid cross-appeal (see Frederick v. Younger Van Lines, 74 N.M. 320, 393 P.2d 438 (1964)) conditioned on a reversal in the appeal proper. Since we do reverse we consider plaintiff’s two points: (1) the trial court erred in instructing that the burden of proving lack of consent and lack of adequate disclosure was on plaintiff; and, (2) the trial court erred in twice instructing that liability be considered before damages.
Burden of Proof
Plaintiff argues that since the physician-patient relationship is “fiduciary” the burden of proof is on the physician as to the questions of inadequate disclosure prior to gaining consent and the competency of the patient to validly consent. See 54 Am.Jur. Trusts § 602 (1945); Moore v. Webb, 345 S.W.2d 239 (Mo.App.1961). We held in our prior opinion in this case, Demers v. Gerety, (Ct.App.), supra, that the physician-patient relationship was fiduciary in nature. By that description we meant only that “utmost good faith toward the patient” is required in disclosure of the possible consequences of medical treatment. We did not mean thereby to incorporate the entire law of fiduciaries into malpractice actions.
Failure of a physician to reasonably disclose to a patient all significant facts concerning medical treatment is malpractice. Woods v. Brumlop, 71 N.M. 221, 377 P.2d 520 (1962). In malpractice actions the burden of proof rests on the plaintiff. Witzke v. Dettweiler, 83 N.M. 802, 498 P.2d 689 (Ct.App.1972). We agree with the courts that have found no reason to arbitrarily except “inadequate disclosure” cases from this rule. Funke v. Fieldman, 212 Kan. 524, 512 P.2d 539 (1973); Haven v. Randolph, 342 F.Supp. 538 (D.C.D.C., 1972) ; Conrey v. McGehee, 473 S.W.2d 617 (Tex.Civ.App.1971); Kaplan v. Haines, 96 N.J.Super. 242, 232 A.2d 840 (1967).
Further, competency is presumed in the law. Grannum v. Berard, 70 Wash.2d 304, 422 P.2d 812, 25 A.L.R.3d 1434 (1967); 61 Am.Jur.2d, Physicians, Surgeons, etc., § 157 (1972). Plaintiff must rebut that presumption; that burden is his. Grannum v. Berard, supra; Dicenzo v. Berg, 340 Pa. 305, 16 A.2d 15 (1940).
As part of this point plaintiff objects to the trial court’s instruction No. 10, which states:
“It is the duty of every person to read an instrument before he signs it, if he can read. If he cannot read or understand an instrument, it is his duty to have the instrument read and explained to him before he signs it. If he fails to do so, he cannot claim that his intentions were other than is represented in the instrument.”
Plaintiff correctly objected. This instruction erroneously failed to recognize that if a party is incompetent (or under such sedation as would destroy competency) at the time of entering in a contract, that agreement is invalid. Pilon v. Lobato, 54 N.M. 218, 219 P.2d 290 (1950); Morgan v. Thompson et ah, 46 N.M. 282, 127 P.2d 1037 (1942). No other instruction covered the point.
Repetitious Instructions
Plaintiff argues that the giving of U.J.I. Nos. 14.1 and 17.8 unduly emphasized, by repetition, the “consideration of liability before damages” instruction. This argument is without merit. Clinard v. Southern Pacific Company, 82 N.M. 55, 475 P.2d 321 (1970) states: “. . . our U.J.I. requires that both 14.1 and 17.8 are to be given, purposely to cover the subject-matter twice.” [Emphasis added]. Also see Tafoya v. Whitson, 83 N.M. 23, 487 P.2d 1093 (Ct.App. 1971).
The case is reversed and remanded to the trial court for a new trial consistent with this opinion.
It is so ordered.
HERNANDEZ, J., concurs. SUTIN, J., dissents.