McKenna (P) had severe cerebral damage as a result of hypertension caused by her use of a contraceptive manufactured by Ortho (D). This emanated from a catastrophic cerebrovascular stroke from using the contraceptive. P sued in federal court in Pennsylvania. That court directed a verdict for D; the court held that the Pennsylvania borrowing statute, which is the statute of limitations of Ohio where the cause of action arose, applied to the case and it barred the suit. P appealed; the standard to determine when the cause of action arose would be determined under Pennsylvania law, where the suit would not have been barred.