The rape-related diagnoses currently used in expert testimony include rape trauma syndrome (RTS), posttraumatic stress disorder (PTSD), and acute stress disorder. PTSD is the strongest rape-related diagnosis on which to base educational expert testimony, but several limitations in this diagnosis prevent courts from being able to use it as a litmus test for rape. The two sets of measures taken to assess PTSD assess the trauma and the symptoms. The five levels of testimony in rape cases include: (1) testimony on specific behaviors of rape survivors that the defense describes as unusual, (2) testimony on the common reactions to rape and the general diagnostic criteria for RTS or PTSD, (3) expert opinion on the consistency of a victim’s behavior or symptoms with RTS or PTSD, (4) testimony stating that the victim suffers from RTS or PTSD, and (5) expert opinion that goes beyond a diagnosis. Sufficient empirical knowledge now appears to exist to allow experts to discuss the PTSD diagnosis of a particular victim, but only if they first acknowledge the limitations of the validity of the diagnosis and of the reliability of the current measurement tools. Experts need to determine at what level they can testify ethically and must not allow themselves to be pressured into answering questions that exceed these boundaries. 78 references