Upon objection by the defendant, the trial court must find, by clear and convincing evidence, that defendant had the capacity to commit an unadjudicated juvenile offense before admitting the evidence under Evidence Code section 1108. Appellant was charged with lewd acts upon his niece. Over appellant’s objection based on Penal Code section 26(One), the prosecution introduced an unadjudicated sexual abuse offense that appellant allegedly committed at the age of 13 years and 10 months against his younger sister. The jury convicted the defendant. The Court of Appeal reversed for instructional error related to the unadjudicated juvenile sex offense. The Supreme Court reversed and outlined the procedure for admitting this type of evidence when the defendant was under 14 at the time of the offense. Evidence Code section 1108 permits admission of evidence that the defendant committed other sexual offenses to prove his propensity to commit the charged sexual offenses. Sexual offense is defined as a crime under the law of a state or of the United States. Section 26(One) establishes a rebuttable presumption that a child under the age of 14 is incapable of committing a crime. Thus, for prior sexual offense evidence to be admitted, the offense must be a crime, and to be a crime, a child under 14 must appreciate the wrongness of his conduct; i.e., have the capacity to commit the crime. Pursuant to Evidence Code section 405, the determination of capacity, which is a predicate to admissibility, is resolved by the court, with the standard being that of proof by clear and convincing evidence. Although the jury does not determine capacity, it can evaluate the proffered evidence as to whether it demonstrates propensity. The court is not required to instruct the jury sua sponte to consider whether a defendant appreciated the wrongfulness of the prior act as this is a question for the court to resolve, not the jury. The defense may request a pinpoint instruction if it relies on the defendant’s age to undermine the propensity conclusion but such an instruction should not reference section 26(One) or its presumption.