Whether additional genetic testing is required to eliminate a possible alternative cause when an expert has completed a differential diagnosis and explained why that alternative cause was ruled out

QUESTION PRESENTED There now exists a new rule creating a significant split in how District Courts and Courts of Appeals are to interpret and apply Federal Rule of Evidence 702 and this Court’s decision in Daubert v. Merrell Dow Pharms., Inc., 509 U.S. 579 (1993), when determining the admissibility of expert causation testimony. The Courts of Appeals that have addressed this issue agree that if an expert is qualified to testify, employs an accepted methodology, and a defendant points to an alternative cause of a plaintiff’s injury, the expert’s causation opinion should only be excluded when the expert does not provide an explanation as to why that alternative cause was ruled out. In this case, Petitioner’s experts were qualified to testify and employed the accepted methodology of differential diagnosis to rule out a genetic cause for Petitioner’s birth defects. But in an unprecedented interpretation of Rule 702 and Daubert, at odds with other Circuit Courts of Appeals, the Second Circuit found these experts’ opinions inadmissible in that defendant pointed to genetics as a cause, and, despite the experts providing an explanation as to why genetics was ruled out, the Court required additional genetic testing to eliminate the possibility of a genetic cause. No other Circuit Court has held this position. Such unilateral action by the Second Circuit creates uncertainty, confusion and lacks predictability. The question before this Court is thus as follows: For an expert’s causation opinion to be admissible, do Federal Rule of Evidence 702 and Daubert require additional testing of a plaintiff to eliminate the possibility of an alternative cause pointed to by a defendant, where the expert completed a differential diagnosis and explained how that alternative cause was ruled out?