American Cyanamid was not required to present evidence to refute plaintiff's claims against it because plaintiff failed to present a prima facie case on the issue of causation based on childhood exposure. See, Hebert v. Cleans-It, 96-1566 (La.App. 4 Cir. 5/21/97), 695 So.2d 552. I do not question the credentials of Dr. Roggli or Mr. Parker, nor do I find fault in the trial court's decision to accept them as expert witnesses.