In the landmark case of Sindell v. Abbott Laboratories that every law student read in Torts, California enunciated its doctrine of market share liability. The theory is that companies should be obligated to pay according to how much market share they had when product identifcation cannot be established.
Twenty-five years have passed since Sindell came along to change the future of mass tort cases where multiple defendants might be responsible. But it has not caught on in Maryland or in most states.
Our courts have explictly rejected this doctrine, requring plaintiffs in pharmaceutical cases to prove which defendant manufactured the product that caused the injury. Most jurisdictions seems to adopt this approach or have tightly confined Sindell to its facts. The Court of Appeals underscored its thoughts on market share liability in Maryland most recently in Reiter v. ACandS, 179 Md. App. 645 (2008).
The reality is that the DES cases were relatively unusual. Women who took DES and initially had no symptoms. It took sometimes more than 20 years before their children were being diagnosed with cancer as a result. Many companies had made the exact same product and it was impossible to know all of these years later who the specific manufacturer was for each woman. This made proof nearly impossible and you can see why the court may have felt compelled to create this doctrine for those cases.