State v. Tanner
In State v. Tanner, 675 P.2d 539 (Utah 1983), the Court held that in cases of child abuse, including child sexual abuse, "evidence of specific instances of the defendant's treatment of the child is relevant to establish not merely a general disposition for violence or ill-will towards all children, but to establish a specific pattern of behavior by the defendant toward one particular child, the victim." Id. at 546.
The Court held that battered child syndrome evidence is admissible to prove non-accidental injuries when given by properly qualified expert witness.
The Court expressly stated that "the expert should be able to testify in detail regarding the nature of the child's injuries and whether the explanation given for the injuries is reasonable." 675 P.2d at 544.
Moreover, the Court stated that an expert opinion with regard to the existence of battered child syndrome is not an opinion as to a defendant's culpability. 675 P.2d at 542.