MOSK, Justice.
This case involves a complex problem both timely and significant: may a plaintiff, injured as the result of a drug administered to her mother during pregnancy, who knows the type of drug involved but cannot identify the manufacturer of the precise product, hold liable for her injuries a maker of a drug produced from an identical formula?

Plaintiff Judith Sindell brought an action against eleven drug companies and Does 1 through 100, on behalf of herself and other women similarly situated. The complaint alleges as follows:

Between 1941 and 1971, defendants were engaged in the business of manufacturing, promoting, and marketing diethylstilbesterol (DES), a drug which is a synthetic compound of the female hormone estrogen. The drug was administered to plaintiff's mother and the mothers of the class she represents, [FN1] for the purpose of preventing miscarriage. In 1947, the Food and Drug Administration authorized the marketing of DES as a miscarriage preventative, but only on an experimental basis, with a requirement that the drug contain a warning label to that effect.


FN1. The plaintiff class alleged consists of “girls and women who are residents of California and who have been exposed to DES before birth and who may or may not know that fact or the dangers” to which they were exposed. Defendants are also sued as representatives of a class of drug manufacturers which sold DES after 1941.


*594 DES may cause cancerous vaginal and cervical growths in the daughters exposed to it before birth, because their mothers took the drug during pregnancy. The form of cancer from which these daughters suffer is known as adenocarcinoma, and it manifests itself after a minimum latent period of 10 or 12 years. It is a fast-spreading and deadly disease, and radical surgery is required to prevent it from spreading. DES also causes adenosis, precancerous vaginal and cervical growths which may spread to other areas of the body. The treatment for adenosis is cauterization, surgery, or cryosurgery. Women who suffer from this condition must be monitored by biopsy or colposcopic examination twice a year, a painful and expensive procedure. Thousands of women whose mothers received DES during pregnancy are unaware of the effects of the drug.

In 1971, the Food and Drug Administration ordered defendants to cease marketing and promoting DES for the purpose of preventing miscarriages, and to warn physicians and the public that the drug should not be used by pregnant women because of the danger to their unborn children.

During the period defendants marketed DES, they knew or should have known that it was a carcinogenic substance, that there was a grave danger after varying periods of latency it would cause cancerous and precancerous growths in the daughters of the mothers who took it, and that it was ineffective***134 **926 to prevent miscarriage. Nevertheless, defendants continued to advertise and market the drug as a miscarriage preventative. They failed to test DES for efficacy and safety; the tests performed by others, upon which they relied, indicated that it was not safe or effective. In violation of the authorization of the Food and Drug Administration, defendants marketed DES on an unlimited basis rather than as an experimental drug, and they failed to warn of its potential danger. #p#分页标题#e#

I

Plaintiff places primary reliance upon cases which hold that if a party cannot identify which of two or more defendants caused an injury, the burden of proof may shift to the defendants to show that they were not responsible for the harm. This principle is sometimes referred to as the “alternative liability” theory.

The celebrated case of Summers v. Tice, supra, 33 Cal.2d 80, 199 P.2d 1, a unanimous opinion of this court, best exemplifies the rule. In Summers, the plaintiff was injured when two hunters negligently shot in his direction. It could not be determined which of them had fired the shot which *599 actually caused the injury to the plaintiff's eye, but both defendants were nevertheless held jointly and severally liable for the whole of the damages. We reasoned that both were wrongdoers, both were negligent toward the plaintiff, and that it would be unfair to require plaintiff to isolate the defendant responsible, because if the one pointed out were to escape liability, the other might also, and the plaintiff-victim would be shorn of any remedy. In these circumstances, we held, the burden of proof shifted to the defendants, “each to absolve himself if he can.” (Id., p. 86, 199 P.2d p. 4.) We stated that under these or similar circumstances a defendant is ordinarily in a “far better position” to offer evidence to determine whether he or another defendant caused the injury.

In Summers, we relied upon Ybarra v. Spangard (1944) 25 Cal.2d 486, 154 P.2d 687. There, the plaintiff was injured while he ***137 **929 was unconscious during the course of surgery. He sought damages against several doctors and a nurse who attended him while he was unconscious. We held that it would be unreasonable to require him to identify the particular defendant who had performed the alleged negligent act because he was unconscious at the time of the injury and the defendants exercised control over the instrumentalities which caused the harm. Therefore, under the doctrine of res ipsa loquitur, an inference of negligence arose that defendants were required to meet by explaining their conduct.

The rule developed in Summers has been embodied in the Restatement of Torts. (Rest.2d Torts, s 433B, subsec. (3).) [FN11] Indeed, the Summers facts are used as an illustration (p. 447).

Defendants assert that these principles are inapplicable here. First, they insist that a predicate to shifting the burden of proof under Summers-Ybarra is that the defendants must have greater access to information regarding the cause of the injuries than the plaintiff, whereas in the present case the reverse appears.

Plaintiff does not claim that defendants are in a better position than she to identify the manufacturer of the drug taken by her mother or, indeed, that they have the ability to do so at all, but argues, rather, that Summers does not impose such a requirement as a condition to the shifting of the burden of proof. In this respect we believe plaintiff is correct. #p#分页标题#e#

In Summers, the circumstances of the accident themselves precluded an explanation of its cause. To be sure, Summers states that defendants are “(o) rdinarily . . . in a far better position to offer evidence to determine which one caused the injury” than a plaintiff (33 Cal.2d 80, at p. 86, 199 P.2d 1 at p. 4), but the decision does not determine that this “ordinary” situation was present. Neither the facts nor the language of the opinion indicate that the two defendants, simultaneously shooting in the same direction, were in a better position than the plaintiff to ascertain whose shot caused the injury. As the opinion acknowledges, it was impossible for the trial court to determine whether the shot which entered the plaintiff's eye came from the gun of one defendant or the other. Nevertheless, burden of proof was shifted to the defendants.

Here, as in Summers, the circumstances of the injury appear to render identification of the manufacturer of the drug ingested by plaintiff's mother impossible by either plaintiff or defendants, and it cannot reasonably be said that one is in a better position than the other to make the identification. Because many years elapsed between the time the drug was taken and the manifestation of plaintiff's injuries she, and many other daughters of mothers who took DES, are unable to make such identification.***138 **930 [FN12] Certainly there can be no implication that plaintiff *601 is at fault in failing to do so the event occurred while plaintiff was in utero, a generation ago.[FN13]

On the other hand, it cannot be said with assurance that defendants have the means to make the identification. In this connection, they point out that drug manufacturers ordinarily have no direct contact with the patients who take a drug prescribed by their doctors. Defendants sell to wholesalers, who in turn supply the product to physicians and pharmacies. Manufacturers do not maintain records of the persons who take the drugs they produce, and the selection of the medication is made by the physician rather than the manufacturer. Nor do we conclude that the absence of evidence on this subject is due to the fault of defendants. While it is alleged that they produced a defective product with delayed effects and without adequate warnings, the difficulty or impossibility of identification results primarily from the passage of time rather than from their allegedly negligent acts of failing to provide adequate warnings. Thus Haft v. Lone Palm Hotel (1970) 3 Cal.3d 756, 91 Cal.Rptr. 745, 478 P.2d 465, upon which plaintiff relies, is distinguishable.

It is important to observe, however, that while defendants do not have means superior to plaintiff to identify the maker of the precise drug *602 taken by her mother, they may in some instances be able to prove that they did not manufacture the injury-causing substance. In the present case, for example, one of the original defendants was dismissed from the action upon proof that it did not manufacture DES until after plaintiff was born. #p#分页标题#e#

Thus we conclude that the fact defendants do not have greater access to information which might establish the identity of the manufacturer of the DES which injured plaintiff does not per se prevent application of the Summers rule.

[2] Nevertheless, plaintiff may not prevail in her claim that the Summers rationale should be employed to fix the whole liability for her injuries upon defendants, at least as those principles have previously been applied.[FN15] There is an important difference***139 **931 between the situation involved in Summers and the present case. There, all the parties who were or could have been responsible for the harm to the plaintiff were joined as defendants. Here, by contrast, there are approximately 200 drug companies which made DES, any of which might have manufactured the injury-producing drug.[FN16]

Defendants maintain that, while in Summers there was a 50 percent chance that one of the two defendants was responsible for the plaintiff's injuries, here since any one of 200 companies which manufactured DES *603 might have made the product which harmed plaintiff, there is no rational basis upon which to infer that any defendant in this action caused plaintiff's injuries, nor even a reasonable possibility that they were responsible.[FN17]

These arguments are persuasive if we measure the chance that any one of the defendants supplied the injury-causing drug by the number of possible tortfeasors. In such a context, the possibility that any of the five defendants supplied the DES to plaintiff's mother is so remote that it would be unfair to require each defendant to exonerate itself. There may be a substantial likelihood that none of the five defendants joined in the action made the DES which caused the injury, and that the offending producer not named would escape liability altogether. While we propose, infra, an adaptation of the rule in Summers which will substantially overcome these difficulties, defendants appear to be correct that the rule, as previously applied, cannot relieve plaintiff of the burden of proving the identity of the manufacturer which made the drug causing her injuries.[FN18]

II

The second principle upon which plaintiff relies is the so-called “concert of action” theory. Preliminarily, we briefly describe the procedure a drug manufacturer must follow before placing a drug on the market. Under federal law as it read prior to 1962, a new drug was defined as one “not generally ***140 **932 recognized as . . . safe.” (s 102, 76 Stat. 781 (Oct. 10, 1962).) Such a substance could be marketed only if a new drug application*604 had been filed with the Food and Drug Administration and had become “effective.” [FN19] If the agency determined that a product was no longer a “new drug,” i. e., that it was “generally recognized as . . . safe,” ( 21 U.S.C.A. s 321, subd. (p) (1)) it could be manufactured by any drug company without submitting an application to the agency. According to defendants, 123 new drug applications for DES had been approved by 1952, and in that year DES was declared not to be a “new drug,” thus allowing any manufacturer to produce it without prior testing and without submitting a new drug application to the Food and Drug Administration. #p#分页标题#e#

With this background we consider whether the complaint states a claim based upon “concert of action” among defendants. The elements of this doctrine are prescribed in section 876 of the Restatement of Torts. The section provides, “For harm resulting to a third person from the tortious conduct of another, one is subject to liability if he (a) does a tortious act in concert with the other or pursuant to a common design with him, or (b) knows that the other's conduct constitutes a breach of duty and gives substantial assistance or encouragement to the other so to conduct himself, or (c) gives substantial assistance to the other in accomplishing a tortious result and his own conduct, separately considered, constitutes a breach of duty to the third person.” With respect to this doctrine, Prosser states that “those who, in pursuance of a common plan or design to commit a tortious act, actively take part in it, or further it by cooperation or request, or who lend aid or encouragement to the wrongdoer, or ratify and adopt his acts done for their benefit, are equally liable with him. (P) Express agreement is not necessary, and all that is required is that there be a tacit understanding . . . .” (Prosser, Law of Torts (4th ed. 1971), sec. 46, p. 292.)

Plaintiff contends that her complaint states a cause of action under these principles. She alleges that defendants' wrongful conduct “is the result of planned and concerted action, express and implied agreements, collaboration in, reliance upon, acquiescence in and ratification, exploitation and adoption of each other's testing, marketing *605 methods, lack of warnings . . . and other acts or omissions . . .” and that “acting individually and in concert, (defendants) promoted, approved, authorized, acquiesced in, and reaped profits from sales” of DES. These allegations, plaintiff claims, state a “tacit understanding” among defendants to commit a tortious act against her.

[3] In our view, this litany of charges is insufficient to allege a cause of action under the rules stated above. The gravamen of the charge of concert is that defendants failed to adequately test the drug or to give sufficient warning of its dangers and that they relied upon the tests performed by one another and took advantage of each others' promotional and marketing techniques. These allegations do not amount to a charge that there was a tacit understanding or a common plan among defendants to fail to conduct adequate tests or give sufficient warnings, and that they substantially aided and encouraged one another in these omissions.

The complaint charges also that defendants produced DES from a “common and mutually agreed upon formula,” allowing pharmacists to treat the drug as a “fungible commodity” and to fill prescriptions from whatever brand of DES they had on hand at the time. It is difficult to understand how these allegations can form the basis of a cause of action for wrongful conduct by ***141 **933 defendants, acting in concert. The formula for DES is a scientific constant. It is set forth in the United States Pharmacopoeia, and any manufacturer producing that drug must, with exceptions not relevant here, utilize the formula set forth in that compendium. (21 U.S.C.A. s 351, subd. (b).) #p#分页标题#e#

What the complaint appears to charge is defendants' parallel or imitative conduct in that they relied upon each others' testing and promotion methods. But such conduct describes a common practice in industry: a producer avails himself of the experience and methods of others making the same or similar products. Application of the concept of concert of action to this situation would expand the doctrine far beyond its intended scope and would render virtually any manufacturer liable for the defective products of an entire industry, even if it could be demonstrated that the product which caused the injury was not made by the defendant.

None of the cases cited by plaintiff supports a conclusion that defendants may be held liable for concerted tortious acts. They involve *606 conduct by a small number of individuals whose actions resulted in a tort against a single plaintiff, usually over a short span of time, and the defendant held liable was either a direct participant in the acts which caused damage,[FN20] or encouraged and assisted the person who directly caused the injuries by participating in a joint activity.

Orser v. George (1967) 252 Cal.App.2d 660, 60 Cal.Rptr. 708 upon which plaintiff primarily relies, is also distinguishable. There, three hunters negligently shot at a mudhen in decedent's direction. Two of them shot alternately with the gun which released the bullet resulting in the fatal wound, and the third, using a different gun, fired alternately at the same target, shooting in the same line of fire, perhaps acting tortiously. It was held that there was a possibility the third hunter knew the conduct of the others was tortious toward the decedent and gave them substantial assistance and encouragement, and that it was also possible his conduct, separately considered, was a breach of duty toward decedent. Thus, the granting of summary judgment was reversed as to the third hunter.

The situation in Orser is similar to Agovino v. Kunze, supra, 181 Cal.App.2d 591, 5 Cal.Rptr. 534, in which liability was imposed upon a participant in a drag race, rather than to the facts alleged in the present case. There is no allegation here that each defendant knew the other defendants' conduct was tortious toward plaintiff, and that they assisted and encouraged one another to inadequately test DES and to provide inadequate warnings. Indeed, it seems dubious whether liability on the concert of action theory can be predicated upon substantial assistance and encouragement given by one alleged tortfeasor to another pursuant to a tacit understanding to fail to perform an act. Thus, there was no concert of action among defendants within the meaning of that doctrine.

*607 III

A third theory upon which plaintiff relies is the concept of industry-wide liability, or according to the terminology of the parties, “enterprise liability.” This theory was suggested in **934 ***142 Hall v. E. I. Du Pont de Nemours & Co., Inc. (E.D.N.Y.1972) 345 F.Supp. 353. In that case, plaintiffs were 13 children injured by the explosion of blasting caps in 12 separate incidents which occurred in 10 different states between 1955 and 1959. The defendants were six blasting cap manufacturers, comprising virtually the entire blasting cap industry in the United States, and their trade association. There were, however, a number of Canadian blasting cap manufacturers which could have supplied the caps. The gravamen of the complaint was that the practice of the industry of omitting a warning on individual blasting caps and of failing to take other safety measures created an unreasonable risk of harm, resulting in the plaintiffs' injuries. The complaint did not identify a particular manufacturer of a cap which caused a particular injury.[FN22] #p#分页标题#e#

The court reasoned as follows: there was evidence that defendants, acting independently, had adhered to an industry-wide standard with regard to the safety features of blasting caps, that they had in effect delegated some functions of safety investigation and design, such as labelling, to their trade association, and that there was industry-wide cooperation in the manufacture and design of blasting caps. In these circumstances, the evidence supported a conclusion that all the defendants*608 jointly controlled the risk. Thus, if plaintiffs could establish by a preponderance of the evidence that the caps were manufactured by one of the defendants, the burden of proof as to causation would shift to all the defendants. The court noted that this theory of liability applied to industries composed of a small number of units, and that what would be fair and reasonable with regard to an industry of five or ten producers might be manifestly unreasonable if applied to a decentralized industry composed of countless small producers.

Plaintiff attempts to state a cause of action under the rationale of Hall. She alleges joint enterprise and collaboration among defendants in the production, marketing, promotion and testing of DES, and “concerted promulgation and adherence to industry-wide testing, safety, warning and efficacy standards” for the drug. We have concluded above that allegations that defendants relied upon one another's testing and promotion methods do not state a cause of action for concerted conduct to commit a tortious act. Under the theory of industry-wide liability, however, each manufacturer could be liable for all injuries caused by DES by virtue of adherence to an industry-wide standard of safety.

In the Fordham Comment, the industry-wide theory of liability is discussed and ***143 **935 refined in the context of its applicability to actions alleging injuries resulting from DES. The author explains causation under that theory as follows, “. . . (T)he industrywide standard becomes itself the cause of plaintiff's injury, just as defendants' joint plan is the cause of injury in the traditional concert of action plea. Each defendant's adherence perpetuates this standard, which results in the manufacture of the particular, unidentifiable injury-producing product. Therefore, each industry member has contributed to plaintiff's injury.” (Fordham Comment, supra, at p. 997.)

The Comment proposes seven requirements for a cause of action based upon industry-wide liability, and suggests that if a plaintiff *609 proves these elements, the burden of proof of causation should be shifted to the defendants, who may exonerate themselves only by showing that their product could not have caused the injury.

We decline to apply this theory in the present case. At least 200 manufacturers produced DES; Hall, which involved 6 manufacturers representing the entire blasting cap industry in the United States, cautioned against application of the doctrine espoused therein to a large number of producers. (345 F.Supp. at p. 378.) Moreover, in Hall, the conclusion that the defendants jointly controlled the risk was based upon allegations that they had delegated some functions relating to safety to a trade association. There are no such allegations here, and we have concluded above that plaintiff has failed to allege liability on a concert of action theory. #p#分页标题#e#

Equally important, the drug industry is closely regulated by the Food and Drug Administration, which actively controls the testing and manufacture of drugs and the method by which they are marketed, including the contents of warning labels.[FN26] To a considerable degree, therefore, the standards followed by drug manufacturers are suggested or compelled by the government. Adherence to those standards cannot, of course, absolve a manufacturer of liability to which it would otherwise be subject. (*610 Stevens v. Parke, Davis & Co. (1973) 9 Cal.3d 51, 65, 107 Cal.Rptr. 45, 507 P.2d 653.) But since the government plays such a pervasive role in formulating the criteria for the testing and marketing of drugs, it would be unfair to impose upon a manufacturer liability for injuries resulting from the use of a drug which it did not supply simply because it followed the standards of the industry. [FN27]

***144 **936 IV

If we were confined to the theories of Summers and Hall, we would be constrained to hold that the judgment must be sustained. Should we require that plaintiff identify the manufacturer which supplied the DES used by her mother or that all DES manufacturers be joined in the action, she would effectively be precluded from any recovery. As defendants candidly admit, there is little likelihood that all the manufacturers who made DES at the time in question are still in business or that they are subject to the jurisdiction of the California courts. There are, however, forceful arguments in favor of holding that plaintiff has a cause of action.

In our contemporary complex industrialized society, advances in science and technology create fungible goods which may harm consumers and which cannot be traced to any specific producer. The response of the courts can be either to adhere rigidly to prior doctrine, denying recovery to those injured by such products, or to fashion remedies to meet these changing needs. Just as Justice Traynor in his landmark concurring opinion in Escola v. Coca Cola Bottling Company (1944) 24 Cal.2d 453, 467-468, 150 P.2d 436, recognized that in an era of mass production and complex marketing methods the traditional standard of negligence was insufficient to govern the obligations of manufacturer to consumer, so should we acknowledge that some adaptation of the rules of causation and liability may be appropriate in these recurring circumstances. The Restatement comments that modification of the Summers rule may be necessary in a situation like that before us. (See fn. 16, ante.)

The most persuasive reason for finding plaintiff states a cause of action is that advanced in Summers : as between an innocent plaintiff and *611 negligent defendants, the latter should bear the cost of the injury. Here, as in Summers, plaintiff is not at fault in failing to provide evidence of causation, and although the absence of such evidence is not attributable to the defendants either, their conduct in marketing a drug the effects of which are delayed for many years played a significant role in creating the unavailability of proof. #p#分页标题#e#

From a broader policy standpoint, defendants are better able to bear the cost of injury resulting from the manufacture of a defective product. As was said by Justice Traynor in Escola, “(t)he cost of an injury and the loss of time or health may be an overwhelming misfortune to the person injured, and a needless one, for the risk of injury can be insured by the manufacturer and distributed among the public as a cost of doing business.” (24 Cal.2d p. 462, 150 P.2d p. 441; see also Rest.2d Torts, s 402A, com. c, pp. 349-350.) The manufacturer is in the best position to discover and guard against defects in its products and to warn of harmful effects; thus, holding it liable for defects and failure to warn of harmful effects will provide an incentive to product safety. (Cronin v. J.B.E. Olson Corp. (1972) 8 Cal.3d 121, 129, 104 Cal.Rptr. 433, 501 P.2d 1153; Beech Aircraft Corp. v. Superior Court (1976) 61 Cal.App.3d 501, 522-523, 132 Cal.Rptr. 541.) These considerations are particularly significant where medication is involved, for the consumer is virtually helpless to protect himself from serious, sometimes permanent, sometimes fatal, injuries caused by deleterious drugs.

[5] Where, as here, all defendants produced a drug from an identical formula and the manufacturer of the DES which caused plaintiff's injuries cannot be identified through no fault of plaintiff, a modification of the rule of Summers is warranted. As we have seen, an undiluted Summers rationale is inappropriate to shift the burden of proof of causation to defendants because if we measure the chance that any particular manufacturer supplied the injury-causing product by the number of producers of DES, there is a possibility that none of the five defendants in this case produced ***145 **937 the offending substance and that the responsible manufacturer, not named in the action, will escape liability.

But we approach the issue of causation from a different perspective: we hold it to be reasonable in the present context to measure the likelihood that any of the defendants supplied the product which allegedly injured plaintiff by the percentage which the DES sold by each of them for the purpose of preventing miscarriage bears to the entire production *612 of the drug sold by all for that purpose. Plaintiff asserts in her briefs that Eli Lilly and Company and 5 or 6 other companies produced 90 percent of the DES marketed. If at trial this is established to be the fact, then there is a corresponding likelihood that this comparative handful of producers manufactured the DES which caused plaintiff's injuries, and only a 10 percent likelihood that the offending producer would escape liability.[FN28]

If plaintiff joins in the action the manufacturers of a substantial share of the DES which her mother might have taken, the injustice of shifting the burden of proof to defendants to demonstrate that they could not have made the substance which injured plaintiff is significantly diminished. While 75 to 80 percent of the market is suggested as the requirement by the Fordham Comment (at p. 996), we hold only that a substantial percentage is required. #p#分页标题#e#

The presence in the action of a substantial share of the appropriate market also provides a ready means to apportion damages among the defendants. Each defendant will be held liable for the proportion of the judgment represented by its share of that market unless it demonstrates that it could not have made the product which caused plaintiff's injuries. In the present case, as we have see, one DES manufacturer was dismissed from the action upon filing a declaration that it had not manufactured DES until after plaintiff was born. Once plaintiff has met her burden of joining the required defendants, they in turn may cross-complaint against other DES manufacturers, not joined in the action, which they can allege might have supplied the injury-causing product.

Under this approach, each manufacturer's liability would approximate its responsibility for the injuries caused by its own products. Some minor discrepancy in the correlation between market share and liability is inevitable; therefore, a defendant may be held liable for a somewhat different percentage of the damage than its share of the appropriate *613 market would justify. It is probably impossible, with the passage of time, to determine market share with mathematical exactitude. But just as a jury cannot be expected to determine the precise relationship between fault and liability in applying the doctrine of comparative fault (Li v. Yellow Cab Co. (1975) 13 Cal.3d 804, 119 Cal.Rptr. 858, 532 P.2d 1226) or partial indemnity (American Motorcycle Ass'n v. Superior Court (1978) 20 Cal.3d 578, 146 Cal.Rptr. 182, 578 P.2d 899), the difficulty of apportioning damages among the defendant producers in exact relation to their market share does not seriously militate against the rule we adopt. As we said in Summers with regard to the liability of independent tortfeasors, where a correct division of liability cannot be made “the trier of fact may make it the best it can.” (33 Cal.2d at p. 88, 199 P.2d at p. 5.)

We are not unmindful of the practical problems involved in defining the market and determining market share,[FN29] but these ***146 **938 are largely matters of proof which properly cannot be determined at the pleading stage of these proceedings. Defendants urge that it would be both unfair and contrary to public policy to hold them liable for plaintiff's injuries in the absence of proof that one of them supplied the drug responsible for the damage. Most of their arguments, however, are based upon the assumption that one manufacturer would be held responsible for the products of another or for those of all other manufacturers if plaintiff ultimately prevails. But under the rule we adopt, each manufacturer's liability for an injury would be approximately equivalent to the damages caused by the DES it manufactured.[FN30]

The judgments are reversed.