Wrongful birth is a legal cause of action in some common law countries in which the parents of a congenitally diseased child claim that their doctor failed to properly warn of their risk of conceiving or giving birth to a child with serious genetic or congenital abnormalities. Thus, the plaintiffs claim, the defendant prevented them from making a truly informed decision as to whether or not to have the child. Wrongful birth is a type of medical malpractice tort. It is distinguished from wrongful life, in which the child sues the doctor. Elements An example of the general elements of a wrongful birth claim, as established by the California Supreme Court, are: the existence of a patient–doctor relationship between the defendant and the plaintiff; the doctor negligently failed to disclose to the prospective parents the risk of having a child with a genetic or congenital disease; the plaintiff suffered harm; and the doctor's negligence caused that harm. Patient–doctor relationship The plaintiff must establish the existence of a patient–doctor relationship by showing that the doctor gave the plaintiff a medical diagnosis or medical advice. Negligence In a wrongful birth case, the plaintiff must show that the doctor failed to follow the standard of care with respect the diagnosis or disclosure of the plaintiffs' risk of transmitting genetic or congenital abnormalities to their children. If the plaintiffs allege that the defendant failed to properly diagnose the plaintiffs' risk of passing on a genetic disorder or other abnormality, then the plaintiffs must put forth expert testimony as to the standard of care for the diagnosis at issue. Lay juries do not have the necessary knowledge of medical practice to evaluate the conduct of doctors without the assistance of an expert witness. If the plaintiffs allege that the defendant failed to disclose the risk of conceiving a child with an abnormality, then the plaintiffs must show that the doctor had the duty to make the disclosure at issue. Doctors are under an obligation to disclose to their patients the risks of passing on a genetic condition to their prospective children. However, the doctor need not disclose all risks or recommend all available testing procedures. For example, in the case of Munro v. Regents of the University of California, the court held that the doctor was not under an obligation to recommend a Tay–Sachs test when the doctor had no reason to suspect his patients