exposure to nickel and cadmium and the absence of evidence of exposure to other potentially carcinogenic substances such as asbestos or alcohol. These are methodologies that physicians traditionally rely on in diagnosing the cause of a particular patient’s cancer. See Osburn v. Anchor Laboratories, Inc., 825 F.2d 908, 915-16 (5th Cir.1987), cert. denied, 485 U.S. 1009, 108 S.Ct. 1476, 99 L.Ed.2d 705 (1988). The district court should have permitted plaintiffs to present their causation evidence to the jury, which could then “determine the appropriate weight to be given to the testimony.” In re Japanese Elec. Prods. Antitrust Litig., 723 F.2d 238, 278 (3d Cir.1983), rev’d in part on other grounds, 475 U.S. 574, 106 S.Ct. 1348, 89 L.Ed.2d 538 (1986); see Osburn, 825 F.2d at 915 (<HOLDING>). Courts have not required the proof or expert
holding that medical expert opinion testimony that is controversial in its conclusions can support a jury finding of causation as long as the doctors conclusory opinion is based upon wellfounded methodologies holding expert testimony provided no evidence as to causation since testimony was not based upon reasonable medical probability holding that the weight given a treating physicians opinion is limited if the opinion consists only of conclusory statements holding that a conclusory opinion may be rejected holding that lay opinion testimony is not admissible when the jury can readily draw the necessary inferences and conclusions without the aid of the opinion