delivered the decision of the court and the following opinion in which MR. JUSTICE GOLDENHERSH and MR. JUSTICE CLARK join:
This is a negligence action brought by a mother *349individually and on behalf of her minor daughter, Leah Ann Renslow, against defendants, a hospital and its director of laboratories. The trial court dismissed that portion of the complaint which sought damages for the minor (hereinafter, plaintiff), concluding that it had failed to state a cause of action. An appeal under Supreme Court Rule 304(a) (58 Ill. 2d R. 304(a)) was perfected. The appellate court reversed the trial court (40 Ill. App. 3d 234) and issued a certificate of importance. Only the minor plaintiff’s cause of action is before us.
There is but one issue: Does a child, not conceived at the time negligent acts were committed against its mother, have a cause of action against the tortfeasors for its injuries resulting from their conduct?
Plaintiff’s six-count complaint for negligence and willful and wanton misconduct alleges that in October of 1965, when her mother was 13 years of age, the defendants, on two occasions, negligently transfused her mother with 500 cubic centimeters of Rh-positive blood. The mother’s Rh-negative blood was incompatible with, and was sensitized by, the Rh-positive blood. Her mother had no knowledge of an adverse reaction from the transfusions and did not know she had been improperly transfused or that her blood had been sensitized. In December 1973 she first discovered her condition when a routine blood screening was ordered by her physician in the course of prenatal care. Plaintiff further asserts that the defendants discovered they had administered the incompatible blood, but at no time notified her mother or the mother’s family.
The resulting sensitization of the mother’s blood allegedly caused prenatal damage to plaintiff’s hemolitic processes, which put her life in jeopardy and necessitated her induced premature birth. Plaintiff was born on March 25, 1974, jaundiced and suffering from hyperbilirubinemia. She required an immediate, complete exchange transfusion of her blood and another such transfusion *350shortly thereafter. It is further alleged that, as a result of the defendants’ acts, plaintiff suffers from permanent damage to various organs, her brain, and her nervous system.
The trial court dismissed plaintiff’s cause of action because she was not “at the time of the alleged infliction of the injury conceived.” The Fourth District Appellate Court, in a careful and well-reasoned opinion, emphasized that the defendants were a doctor and a hospital, and held that there was no showing “that the defendants could not reasonably have foreseen that the teenage girl would later marry and bear a child and that the child would be injured as the result of the improper blood transfusion.” (40 Ill. App. 3d 234, 239.) The court correctly assessed the distinction between this case and previous cases permitting suit for prenatal injuries. Here, the negligent force, which had its impact upon the infant in its prenatal state, was set in motion years prior to plaintiff’s conception. The court observed that in other types of tort cases “liability has not been barred because the allegedly wrongful conduct occurred long before the resultant injury [when] duty and causation can be established.” (40 Ill. App. 3d 234, 239.) Agreeing with the conclusion reached in Jorgensen v. Meade Johnson Laboratories, Inc. (10th Cir. 1973), 483 F.2d 237, the appellate court found no reason to deny a cause of action to a person simply because he had not yet been conceived at the time of the wrongful conduct.
In 1884, Mr. Justice Holmes rendered a landmark decision, Dietrich v. Inhabitants of Northhampton (1884), 138 Mass. 14, 52 Am. R. 242, denying an action for the wrongful death of a child which did not survive its premature birth. This court, in Allaire v. St. Luke’s Hospital (1900), 184 Ill. 359, followed Dietrich by holding that an action for injuries could not be maintained by a plaintiff who at the time of the injury was a prenatal infant with no separate legal existence. Mr. Justice Boggs’ *351dissent urged that it was “sacrificing truth to a mere theoretical abstraction to say an injury was not to the child but wholly to the mother,” when the fetus was .independently viable at the time of the injury. (184 Ill. 359, 370.) Mr. Justice Boggs pointed out that it was clearly demonstrable that “at a period of gestation in advance of *** parturition the foetus is capable of independent and separate life, and that though within the [mother’s body] it is not merely a part of her body, for her body may die in all of its parts and the child remain alive and capable of maintaining life when separated from the dead body of the mother.” The cases for the next 46 years after Allaire uniformly denied recovery to the prenatally injured plaintiff. Nevertheless, the impact of Mr. Justice Boggs’ dissent eventually turned the tide toward prenatal recovery. Bonbrest v. Kotz (D.D.C. 1946), 65 F. Supp. 138, was the first decision to recognize a common law right of action for prenatal injuries. It relied heavily on Mr. Justice Boggs’ reasoning — that an infant should be recognized as having a legal existence separate from its mother’s at such time as it was capable of sustaining life separate from her. After Bonbrest, there followed what was perhaps the most rapid reversal of a common law tradition, a turnabout documented by this court and others at length. (See Amann v. Faidy (1953), 415 Ill. 422, Chrisafogeorgis v. Brandenberg (1973), 55 Ill. 2d 368, Prosser, Torts, sec. 55, at 335-38 (4th ed. 1971); Annot., 40 A.L.R.3d 1222-71 (1971).) This court, in Amann v. Faidy (1953), 415 Ill. 422, 432, overruled Allaire and held that there is a right of action for the wrongful death of a viable child, injured in útero, who is born alive but thereafter dies. Rodriguez v. Patti (1953), 415 Ill. 496, extended a common law right of action for personal injuries to an infant viable when wrongfully injured in útero. In Chrisafogeorgis v. Brandenberg (1973), 55 Ill. 2d 368, this rationale was further extended to permit a *352wrongful death action for a viable child wrongfully injured in útero and thereafter born dead. By 1972, the initial barriers to a right of action for injury inflicted prenatally had been removed in each jurisdiction where the question had arisen. Comment, Wrongful Birth, the Emerging Status of a New Tort, 8 St. Mary’s L.J. 140, 141 n.5 (1976).
Although we have not decided whether a surviving infant has a right of action for injuries sustained in útero during a previable state of its development, our appellate courts have answered that question in the affirmative. Sana v. Brown (1962), 35 Ill. App. 2d 425; Daley v. Meier (1961), 33 Ill. App. 2d 218. See also Rapp v. Hiemenz (1969), 107 Ill. App. 2d 382, where an action for wrongful death as the result of prenatal injuries to a previable fetus, born dead, was denied.
The complaint in the case sub judice contains no allegation that the plaintiff was viable when her injuries were sustained. We, therefore, must consider whether the plaintiff must allege that she was viable at the time her injuries were sustained.
The rule permitting a cause of action only where the child is viable at the time of the injury has been criticized as a “most unsatisfactory criterion, since [viability] is a relative matter, depending on the health of mother and child and many other matters in addition to the stage of development.” (Prosser, Torts sec. 55, at 337 (4th ed. 1971). See Comment, Negligence and the Unborn Child: A Time for Change, 18 S. Dak. L. Rev. 204, 213-14 (1973); Smith v. Brennan (1960), 31 N.J. 353, 366, 157 A.2d 497, 504.) In addition to the length of pregnancy, viability depends on other factors which include the weight and race of the child and the available life-sustaining techniques. (See Comment, Negligence and the Unborn Child, 18 S. Dak. L. Rev. 204, 215-16 (1973).) Furthermore, it has been pointed out that denial of claims for injuries to the previable fetus may indeed cut off some of the most *353meritorious claims, for there is substantial medical authority that congenital structural defects caused by factors in the prenatal environment can be sustained only early in the previable stages. (Note, The Impact of Medical Knowledge on the Law Relating to Prenatal Injuries, 110 U. Pa. L. Rev. 554, 563 (1962).) Recently, those courts which have considered the question have rejected viability as the deciding factor. (Prosser, Torts sec. 55, at 337 (4th ed. 1971); Annot., 40 A.L.R.3d 1222, 1230 (1971).) Upon reconsideration, we henceforth reject viability as a criterion to a common law action for prenatal injuries. Thus the failure to allege that plaintiff was viable at the time she sustained her injuries does not bar this action. This conclusion, however, does not fully answer the ultimate question of whether a cause of action exists on behalf of a live born infant, although the infant’s injuries resulted from a negligent act occuring prior to her conception. The defendants assert they owed no duty to plaintiff because her injuries were not reasonably foreseeable at the time of the act. The appellate court found this contention erroneous.
The basic understanding of Rh-negative and Rh-positive effects upon hemolitic disease of the newborn has been a medical fact since the 1940’s. (N. Eastman, Williams Obstetrics 1073-74 (12th ed. 1961).) It has long been known that sensitization occurs in 90% of Rh-negative women who have received multiple transfusions of Rh-positive blood (W. Nelson, Textbook of Pediatrics 1034 (8th ed. 1964)), and that about 85% of white Americans and a higher percentage of American Negroes and Chinese are Rh-positive (N. Eastman, Williams Obstetrics 1074, 1076, 1078 (12th ed. 1961)). It has been likewise long known that the Rh-positive fetus of an Rh-negative woman previously sensitized is “at high risk.” (S. Robbins, Pathologic Basis of Disease 557 (1974).) Thus, it has been pointed out that “it must be an absolute *354rule that Rh-positive blood is never transfused to an Rh-negative female who is below the age of menopause.” (P. Mollison, Blood Transfusion in Clinical Medicine 418 (1961).) For these reasons, routine Rh typing has been established practice since at least 1961. (N. Eastman, Williams Obstetrics 1080 (12th ed. 1961).) Defendants herein are a doctor and a hospital. At this stage of the proceedings, with the information presented, we are not prepared to conclude that the harm caused plaintiff was not reasonably foreseeable.
Because the appellate court found the risk of harm reasonably foreseeable, it assumed duty was established, and concluded that the delay between the act and the injury was not a bar to the action.
The implication in the appellate court’s opinion that duty and foreseeability are identical in scope is not altogether correct. In Cunis v. Brennan (1974), 56 Ill. 2d 372, 375, it was pointed out that “the existence of a legal duty is not to be bottomed on the factor of foreseeability alone.” There, quoted with approval, was Dean Leon Green’s observation:
“ ‘ “[H] owever valuable the foreseeability formula may be in aiding a jury or judge to reach a decision on the negligence issue, it is altogether inadequate for use by the judge as a basis of determining the duty issue and its scope. The duty issue, being one of law, is broad in its implication; the negligence issue is confined to the particular case and has no implications for other cases. There are many factors other than foreseeability that may condition a judge’s imposing or not imposing a duty in the particular case ***.” Green, Foreseeability in Negligence Law, 61 Colum. L. Rev. 1401, 1417-18.’ ” (56 Ill. 2d 372, 375.)
Cunis questioned whether duty was limited by the scope *355of foreseeability. It was there held that no legal duty arises unless harm is reasonably foreseeable. Presented here is another aspect of that question: Are there areas of foreseeable harm in which no duty arises? In some instances, the answer is clearly “Yes.” The law has as yet created no duty to save a person from drowning before one’s eyes, though a boat and rope be at hand. Where a third person is foreseeably injured by the shock of witnessing another harmed or imperiled by a tortfeasor, the courts have been reluctant to find a duty to the third person. Prosser, Torts sec. 56, at 340, sec. 55, at 334 (4th ed. 1971).
Historically, negligence could not be founded upon the breach of a duty owed only to some person other than the plaintiff. (Prosser, Torts sec. 53, at 325 (4th ed. 1971). But see Piper v. Hoard (1887), 107 N.Y. 73, 13 N.E. 626, and James, Scope of Duty in Negligence Cases, 47 Nw. U. L. Rev. 778, 788-89 (1953).) Holmes’ Dietrich and its progeny indicate this duty could be owed only to one with a legally identifiable existence. “[N] egligence in the air, so to speak, will not do.” (Pollock, Torts 361 (14th ed. 1939).) As medical science progressed, the courts took notice that a fetus is a separate human entity prior to birth. It is by now commonly accepted that at conception the egg and sperm unite to jointly provide the genetic material requisite for human life. Thus, various courts have gradually come to recognize that the embryo, from the moment of conception, is a separate organism that can be compensated for negligently inflicted prenatal harm. (See, e.g., Sinkler v. Kneale (1960), 401 Pa. 267, 273, 164 A.2d 93, 96; Smith v. Brennan (1960), 31 N.J. 353, 366, 164 A.2d 497, 504; Bennett v. Hymers (1958), 101 N.H. 483, 485, 147 A.2d 108, 110; Kelly v. Gregory (1953), 282 App. Div. 542, 544, 125 N.Y.S.2d 696, 698.) In the case at bar, the wrongful conduct took place prior to plaintiff’s conception; the plaintiff at the time of the conduct was in *356no sense a separate entity to whom the traditional duty of care could be owed. Plaintiff herein asks us to reexamine our notions of duty, and to find, in essence, a contingent prospective duty to a child not yet conceived but foreseeably harmed by a breach of duty to the child’s mother.-
Various commentators have criticized the concept of duty and have pointed out, we think correctly, that “ ‘duty’ is not sacrosanct in itself, but only an expression of the sum total of those considerations of policy which lead the law to say that the particular plaintiff is entitled to protection.” Prosser, Torts sec. 53, at 325-26 (4th ed. 1971). See Prosser, Palsgraf Revisited, 52 Mich. L. Rev. 1, 15 (1953); White, The Right of Recovery for Prenatal Injuries, 12 La. L. Rev. 383, 401 (1952).
We are aware that two recent cases, Jorgensen v. Meade Johnson Laboratories, Inc. (10th Cir. 1973), 483 F.2d 237, and Park v. Chessin (Sup. Ct. Queens County 1976), 88 Misc. 2d 222, 387 N.Y.S.2d 204, have focused upon causation, rather than upon traditional concepts of duty, in permitting a cause of action based on wrongful conduct prior to the plaintiff’s conception. (See generally Sylvia v. Gobeille (1966), 101 R.I. 76, 79, 220 A.2d 222, 224; Sinkler v. Kneale (1960), 401 Pa. 267, 273, 164 A.2d 93, 96.) It has been aptly observed, however, that “[c] ausation cannot be the answer; in a very real sense the consequences of an act go forward to eternity, and back to the beginning of the world. Any attempt to impose responsibility on such a basis would result in infinite liability for all wrongful acts, which would ‘set society on edge and fill the courts with endless litigation.’ ” (Prosser, Palsgraf Revisited, 52 Mich. L. Rev. 1, 24 (1953).) Thus, policy lines, to some extent arbitrary, must be drawn to narrow an area of actionable causation. We see no inherent advantage to discarding the policy lines, defined traditionally as “duty,” in favor of new *357policy lines which would be necessary to circumscribe actionable causation.
We reaffirm the utility of the concept of duty as a means by which to direct and control the course of the common law. But examples of changing notions of legal duty in the area of products liability, as well as the progressive expansion of duty in prenatal cases already documented, demonstrate that duty is not a static concept.
This court has long recognized that a duty may exist to one foreseeably harmed though he be unknown and remote in time .and place. (Wintersteen v. National Cooperage & Woodenware Co. (1935), 361 Ill. 95, 103. See generally Skinner v. Anderson (Í967), 38 Ill. 2d 455.) Also, derivative actions, such as those of a husband or parent for the loss of the wife’s or child’s services, demonstrate that the law has long recognized that a wrong done to one person may invade the protected rights of one who is intimately related to the first. (See Dini v. Naiditch (1960), 20 Ill. 2d 406.) In these cases, because of the nature of the relationship between the parties harmed, the law recognizes a limited area of transferred negligence. Prosser, Palsgraf Revisited, 52 Mich. L. Rev. 1, 20-22 (1953).
The cases allowing relief to an infant for injuries incurred in its previ able state make it clear that a defendant may be held liable to a person whose existence was not apparent at the time of his act. We therefore find it illogical to bar relief for an act done prior to conception where the defendant would be liable for this same conduct had the child, unbeknownst to him, been conceived prior to his act. We believe that there is a right to be bom free from prenatal injuries foreseeably caused by a breach of duty to the child’s mother.
The extension of duty in such a case is further supported by sound policy considerations. Medical science *358has developed various techniques which can mitigate or, in some cases, totally alleviate a child’s prenatal harm. In light of these substantial medical advances it seems to us that sound social policy requires the extension of duty in this case.
The defendants assert that the need for an end to responsibility, short of perpetual liability for a single wrongful act, dictates that a duty for preconception torts not be imposed. They raise the specter of successive generations of plaintiffs complaining against a single defendant for harm caused by genetic damage done an ancestor in a nuclear accident. While we are aware that there may be similar potential for perpetual claims arising from chemical accident or long-term radiation exposure (see Comment, Radiation and Preconception Injuries: Some Interesting Problems in Tort Law, 28 Sw. L.J. 414 (1974)), the case at bar is clearly distinguishable. The damage alleged is not, by its nature, self-perpetuating, nor is the plaintiff a remote descendant. We feel confident that when such a case is presented, the judiciary will effectively exercise its traditional role of drawing rational distinctions, consonant with current perceptions of justice, between harms which are compensable and those which are not.
The problem of defending stale- claims is also asserted by defendants. They remind us that it is possible that a woman, herself a child when injured by the tortfeasor, could late in life bear an injured child, and that this child, under the present statute of limitations, could wait until majority to bring suit. We think the likelihood of these circumstances occurring is not sufficient reason to bar all suits for reasonably foreseeable injury from preconception torts. Furthermore, the potential for a stale claim is inherent in the extended statute of limitations for a minor’s personal injury action and in our adoption of the discovery rule in certain areas. (See Tom Olesker’s Exciting World of Fashion, Inc. v. Dun & Bradstreet, Inc. (1975), *35961 Ill. 2d 129; Berry v. G.D. Searle & Co. (1974), 56 Ill. 2d 548; Lipsey v. Michael Reese Hospital (1970), 46 Ill. 2d 32; Williams v. Brown Manufacturing Co. (1970), 45 Ill. 2d 418; Rozny v. Marnul (1969), 43 Ill. 2d 54.) The persuasiveness of defendants’ argument further loses force where, as here, suit is brought on behalf of the minor plaintiff shortly after birth.
Logic and sound policy require a finding of legal duty in this case. While the result we reach has not yet been recognized widely, we note that various courts and commentators have asserted that it is not necessary that the legal duty be owed to one in existence at the time of the wrongful act. (See Piper v. Hoard (1887), 107 N.Y. 73, 13 N.E. 626; Zepeda v. Zepeda (1963), 41 Ill. App. 2d 240; Jorgensen v. Meade Johnson Laboratories, Inc. (10th Cir. 1973), 483 F.2d 237; Park v. Chessin (Sup. Ct. Queens County 1976), 88 Misc. 2d 222, 387 N.Y.S.2d 204. See also James, Scope of Duty in Negligence Cases, 47 Nw. U. L. Rev. 778, 788-89 (1953); Note, The Impact of Medical Knowledge on the Law Relating to Prenatal Injuries, 110 U. Pa. L. Rev. 554, 566 n.77 (1962).) (The Scottish Law Commission, in 1973, in response to a question posed by the Lord Advocate of the day, concluded that under present Scottish law redress for prenatal injury is competent even where the defendant’s acts occurred prior to conception. See Case and Comment, Report of the Scottish Law Commission on Antenatal Injury, 1974 Jur. Rev. 83.)
Since the liability announced herein represents an extension of duty to a new class of plaintiffs, we hold that it be given prospective application. Therefore, except as to the plaintiff herein, the rule shall apply only to cases arising out of future conduct. Molitor v. Kaneland Community Unit District No. 302 (1959), 18 Ill. 2d 11, 26-27.
The decision of the appellate court, reversing the trial court’s dismissal of this claim for failure to state a cause of *360action, is therefore affirmed and the cause remanded to the trial court for further proceedings.
Affirmed and remanded.