Opinion ID: 1302539
Heading Depth: 4
Heading Rank: 2

Heading: Alternative Causes of Thyroid Disease.

Text: The district court also did not err in permitting Defendants to cross-examine Plaintiffs' experts on alternative causes of thyroid disease. Plaintiffs' chosen methodology for proving causation was differential diagnosis, which is a process by which an expert compiles a comprehensive list of potential causes and then engages in a process of elimination to reach the most likely cause. See Clausen v. M/V NEW CARISSA, 339 F.3d 1049, 1057-58 (9th Cir.2003). Plaintiffs' experts enumerated possible causes of Plaintiffs' diseases, such as genetic predisposition, pregnancy, and stress, and then eliminated them, leaving radioiodine as the only probable cause. Having put these alternative causes at issue, Plaintiffs could not expect Defendants not to question the experts' rejection of them. Defendants were entitled to impeach the experts' methodology and their underlying conclusions.