delivered the Opinion of the Court.
A jury found defendant, Kathryn Harris, guilty of two counts of felony sexual assault. Defendant appeals. We reverse and remand for a new trial.
We frame the issues as follows:
1. Did the State’s expert witness improperly comment on the credibility of an alleged victim who testified at trial?
*4082. Did the District Court err in allowing the State’s expert witness to identify defendant as the perpetrator of the alleged crimes by testifying as to hearsay statements made to her by the alleged victims during the course of therapy?
3. Did the District Court err in granting the jury’s request to have the testimony of an alleged victim read to it after the case had been submitted to the jury?
During the fall of 1987, defendant was employed as a full-time babysitter for a three-year-old girl, referred to as “Janey Doe,” and a five-year-old boy, referred to as “Robby Roe.” Beginning in about mid-September of that year, Janey began complaining that her bottom hurt. On November 18, 1987, she complained of stomach problems. Later that evening, she fell on the stairs, cried and moaned that her vagina hurt. Janey’s mother, Mrs. Doe, wondering what sort of fall could hurt her vagina, examined Janey and discovered a thick glob of mucous in the vaginal area. When Mrs. Doe wiped the area with a warm washcloth, Janey cried and screamed in pain. Mrs. Doe then noticed that the lip of Janey’s vagina was streaked with blood-like blisters. She also noticed a bruise on Janey’s lower right vagina.
The following day, Mrs. Doe took Janey to her pediatrician for an examination. The pediatrician, who was trained in sexual abuse, discovered a bruise outside of Janey’s vagina, along with abrasions on the side of the vagina. She labeled the injuries as non-accidental and consistent with sexual abuse.
On November 25, 1987, Janey began therapy sessions with Sandi Burns, a psychotherapist specializing in child sexual abuse. During the course of the sessions, Janey told Bums that defendant had put a stick in her vagina, placed a finger in her vagina and hit her vagina with her hands or a stick. In addition, Janey told Burns that defendant’s husband, Eric Harris Cates, stuck his penis in her vagina.
Janey indicated that Robby Roe had also been sexually abused by defendant and her husband. Subsequently, on February 1, 1988, Burns examined Robby. Robby related to Bums stories of sexual abuse by defendant and her husband.
On February 26, 1988, defendant was charged with two counts of felony sexual assault against the minor children in violation of § 45-5-502, MCA. Her husband, Cates, was charged at the same time *409with one count of sexual intercourse without consent against Janey Doe, or, in the alternative, sexual assault, and one count of felony sexual assault against Robby Roe.
The District Court granted the defendants’ motion for separate trials. Cates’ trial was held in July, 1988, in the Fourteenth Judicial District Court, Musselshell County, the county in which the offenses occurred. A jury found Cates guilty of one count of sexual intercourse without consent and one count of sexual assault. On appeal, this Court overturned the sexual intercourse without consent conviction, holding that the evidence was insufficient to sustain the conviction. State v. Cates, 241 Mont. 282, 787 P.2d 319 (1990).
Due to the publicity engendered by the Cates trial, defendant Harris was granted a change of venue from Musselshell County to Gallatin County. Prior to trial, defendant filed a motion in limine seeking to exclude hearsay statements made by Janey to any State witness. Defendant also sought to prohibit Sandi Burns, the children’s therapist, from testifying that the children were sexually assaulted and that they were truthful, credible and consistent. The motions were denied.
Trial commenced on November 14, 1988. Janey did not testify, having been found incompetent by the District Court prior to the Cates trial. Robby, however, did testify, as did the the psychotherapist Bums.
On November 16, 1988, the jury found defendant guilty of two counts of felony sexual assault. Defendant was sentenced to 14 years imprisonment on each count, with seven years suspended, both sentences to run concurrently. This appeal followed.
I.
Did the State’s expert witness improperly comment on the credibility of an alleged victim who testified at trial?
At trial, Sandi Bums, the psychotherapist who examined both Janey and Robby, testified that Robby was “a little, honest, open country boy .... [H]e’s a pretty trustworthy child .... [He] is very honest.” Defendant argues that this testimony constituted an improper comment on Robby’s credibility.
The question of the credibility of an alleged victim lies exclusively within the province of the jury. Expert testimony regarding credibility improperly invades the jury’s function by placing a stamp of scientific legitimacy on the victim’s allegations. Therefore, we *410generally will not allow an expert witness to comment on the credibility of an alleged victim. State v. Brodniak, 221 Mont. 212, 222, 718 P.2d 322, 329 (1986).
We have carved out one exception to this rule. In cases involving sexual abuse of a minor child, we will allow expert testimony on the credibility of the alleged victim. State v. Geyman, 224 Mont. 194, 200, 729 P.2d 475, 479 (1986). This exception applies, however, only when the victim testifies at trial, State v. J. C. E., 235 Mont. 264, 269, 767 P.2d 309, 312-13 (1988), and credibility is brought into question. See State v. Hall, [244 Mont. 161,] 797 P.2d 183, 191, 47 St.Rep. 1501, 1510 (Mont.1990).
In the present case, although Robby testified at trial, his credibility was not attacked by defendant. Defendant did not denigrate Robb/s credibility in an opening statement or cross-examine him when he took the stand. The only time she touched on the issue of credibility was during the cross examination of Robb/s mother when she asked if Robby had at first denied the abuse. The State, however, had opened the door to this line of questioning by bringing the matter up on direct. Because Robby’s credibility was not called into question by defendant, the District Court committed reversible error by allowing the psychotherapist to comment directly on his trustworthiness.
II.
Did the District Court err in allowing the State’s expert witness to identify defendant as the perpetrator of the alleged crimes by testifying as to hearsay statements made to her by the victims during the course of therapy?
As we noted in J. C. E., 235 Mont. at 267-68, 767 P.2d at 311-12, cases involving sexual abuse of young children raise troubling evidentiary questions. When an alleged victim of abuse is a young child who, in a courtroom setting, may be unable to relate information about the alleged offense, probative evidence may be lost. Out-of-court statements made by the child to others therefore become some of the most valuable evidence available. These statements, however, constitute hearsay, and are normally inadmissible in court.
The courts are thus forced to walk a fine line between following the traditional rules of evidence and excluding what might be the most probative, material evidence of the crime. The dilemma is *411especially acute when, as in this case, the criminal defendant’s Sixth Amendment right of confrontation is implicated by the unavailability of a child declarant.
In addition to posing confrontation problems, another danger involved in allowing hearsay statements, especially when they are admitted through an expert witness such as a counselor or psychologist, is that the expert becomes a surrogate witness for the child. While we recognize that expert testimony regarding the sometimes puzzling and seemingly contradictory behavior of victims of child sexual assault may aid the jury to determine ultimate issues, such as whether the crime actually occurred, we must be careful not to allow the witness to become a conduit for otherwise inadmissible testimony.
In J. C. E., 235 Mont. at 269-70, 767 P.2d at 313, we held that the identification of the perpetrator of a crime is not a proper subject for expert testimony under Rule 702, M.R.Evid., which allows expert testimony if it will “assist the trier of fact to understand the evidence,” or Rule 704, M.R.Evid., which allows an expert to render an opinion on an ultimate issue. We noted that an opinion on an ultimate issue may be rendered only if it assists the jury. Whether a child was the victim of sexual abuse is a question that may be clarified by expert testimony. “However, whether the evidence adduced by the State establishes [defendant] as the perpetrator requires only the common logic that is indeed well within the capacity of a lay jury.” J. C. E., 235 Mont. at 270, 767 P.2d at 313.
The State argues that the testimony of psychotherapist Sandi Burns may be admitted through Rule 803(4), M.R.Evid., the medical diagnosis and treatment exception to the hearsay rule. This exception provides as follows:
“The following are not excluded by the hearsay rule, even though the declarant is available as a witness:
“(4) Statements for purposes of medical diagnosis or treatment. Statements made for purposes of medical diagnosis or treatment and describing medical history, or past or present symptoms, pain, or sensations, or the inception or general character of the cause or external source thereof insofar as reasonably pertinent to diagnosis or treatment.”
Rule 803(4), M.R.Evid.
We considered and rejected this contention in J. C. E., 235 Mont. at 271, 767 P.2d at 313, stating, ‘We decline to extend the medical *412diagnosis and treatment exception beyond medical doctors ...” The State urges us to reconsider our ruling and attempts to distinguish the present case from J. C. E. on the grounds that the counselor in that case was unlicensed and therefore without the necessary authority to render, medical diagnosis while the counselor in this case is licensed. The State further points out that the Commission Comments indicate that the exception was not intended to apply only to statements made to medical doctors.
The Commission Comments state:
“The exception allows statements made to any person and about any pertinent subject, so long as within the purpose of the exception.” (Emphasis added.)
Commission Comments to Rule 803(4), M.R.Evid., 3 MCA Annot., Title 26 at 352 (1986).
While we agree with the State that in some cases hearsay statements made to persons other than physicians may be admissible under the medical diagnosis and treatment exception, we once again decline to extend the exception beyond medical doctors in cases involving abuse of young children because we cannot be assured that such statements are “within the purpose of the exception.”
Statements made for purposes of medical diagnosis and treatment must satisfy a two-part test before they come within the purpose of this exception to the hearsay rule. First, the declarant’s motive in making the statement must be consistent with seeking medical treatment. Second, the statement must be of a type reasonably relied on by a physician when making diagnosis and treatment decisions. J. C. E., 235 Mont. at 270, 767 P.2d at 313.
The State argues that hearsay statements made by a child victim of sexual assault to her counselor should be admitted under the medical treatment exception because the counselor relies on the identity of the perpetrator in determining the most appropriate course of treatment for the victim. While we do not doubt that this assertion is correct, it ignores the first requirement of the exception, that is, that the victim or patient understands the need for telling the truth to his or her doctor.
The reliability of the medical treatment exception to the hearsay rule is assured by the first prong of the test. The declarant who seeks medical treatment possesses a selfish motive in telling the truth. He knows that “the effectiveness of the treatment he receives may *413depend largely upon the accuracy of the information he provides.” C. McCormick, McCormick on Evidence § 292 at 839 (E. Cleary 3d Ed. 1984).
In J. C. E., 235 Mont. at 271, 767 P.2d at 314, we noted that the trustworthiness of statements made by a young child to her counselor is not necessarily assured because ££[t]he child might not comprehend the necessity of telling a doctor the truth in order to aid diagnosis and treatment.” Because we cannot be assured of the reliability of statements made by young children to their counselors, we hold that statements made to the child’s counselor cannot be admitted into evidence under the medical treatment exception to the hearsay rule.
The State argues, in the alternative, that the hearsay statements in question may come into evidence under the residual exception to the hearsay rule, Rule 804(b)(5), M.R.Evid., which provides that statements not specifically covered by any of the enumerated exceptions may be admissible if they possess “comparable circumstantial guarantees of trustworthiness.”
In J. C. E., 235 Mont. at 273, 767 P.2d at 315, we noted that hearsay statements made by a minor child who is the alleged victim of sexual abuse and who is unavailable for trial may be admissible under Rule 804(b)(5), M.R.Evid. Such statements are admissible, however, only if the following conditions are present:
“1. The victim must be unavailable as a witness, whether through incompetency, illness or some other like reason (e.g., trauma induced by the courtroom setting).
“2. The proffered hearsay must be evidence of a material fact, and must be more probative than any other evidence available through reasonable means.
“3. The party intending to offer the hearsay testimony must give advance notice of that intention.”
J. C. E., 235 Mont. at 273, 767 P.2d at 315.
With regard to Bums’ testimony involving statements made to her by Janey, it is uncontested that Janey was unavailable as a witness due to incompetency. Therefore, the first condition is satisfied.
The second prerequisite, however, is not satisfied. Although the hearsay statements attested to by Burns identified defendant as the perpetrator of the sexual assaults against Janey and were therefore material, they were not the most probative evidence on the matter. Robby, a victim of the abuse and an eyewitness to the alleged assault against Janey, testified that he saw defendant touch Janey “on the *414‘bagina.’ ” Because Robby was able to link defendant to the sexual assault against Janey, the identification of defendant through hearsay statements was cumulative and served only to bolster Robby’s testimony.
The hearsay testimony regarding Robby’s statements to Burns are inadmissible under Rule 804(b)(5), M.R.Evid., because Robby was available for trial. However, Robby’s hearsay statements could under some circumstances be admitted under Rule 803(24), M.R.Evid., the residual exception to the hearsay rule used when the declarant is available to testify, as long as the statements possess “circumstantial guarantees of trustworthiness.”
The preliminary protections that apply to Rule 804(b)(5), M.R.Evid., also apply to Rule 803(24), M.R.Evid. The proffered hearsay must be evidence of a material fact; the hearsay must be more probative than any other evidence available through reasonable means; and the party intending to offer the hearsay testimony must give advance notice of that intention.
In the present case, we hold that the statements made by Robby to Burns during counseling sessions are inadmissible. Because Robby was available to identify and did indeed identify defendant as the perpetrator of the crime, the hearsay statements to which Burns testified were not the most probative evidence on the matter. As we noted above, Burns’ testimony on this issue was merely cumulative, serving only to bolster Robby’s testimony.
For guidance in future cases, we will now discuss, using the factors set forth in J. C. E., 235 Mont. at 274, 767 P.2d at 315, the conditions under which hearsay testimony by a therapist who is an expert in treating victims of child sexual abuse may be admitted under the residual exceptions of Rule 804(b)(5), M.R.Evid., the exception used when the declarant does not testify, and Rule 803(24), M.R.Evid., the exception used when the declarant does testify. We emphasize that the district courts need reach this analysis only if the preliminary protections of both rules have been satisfied. As we stated above, those protections are, in the case of Rule 804(b)(5), M.R.Evid., the child declarant is unavailable as a witness, the proffered hearsay is the most probative evidence of a material fact, and advance notice has been given of the intent to use the testimony; in the case of Rule 803(24), M.R.Evid., the proffered hearsay is the most probative evidence of a material fact and advance notice has been given of the intent to use the testimony.
*415The factors concerning the attributes of the child hearsay declarant as enumerated in J. C. E., 235 Mont. at 274, 767 P.2d at 315, will vary in each case and are not particularly germane to this discussion. We do note that any time the child has been determined to be incompetent to testify at trial, the child’s ability to communicate verbally (one of the factors) is questionable.
The second group of factors set forth in J. C. E. are:
“a. The witness’s relationship to the child.
“b. Whether the relationship between the witness and the child might have an impact on the trustworthiness of the hearsay statement.
“c. Whether the witness might have a motive to fabricate or distort the child’s statement.
“d. The circumstances under which the witness heard the child’s statement, including the timing of the statement in relation to the incident at issue and the availability of another person in whom the child could confide.”
J. C. E., 235 Mont. at 274, 767 P.2d at 315.
A therapist does not see a child for treatment of the effects of sexual abuse unless there has been a claim that the child has been sexually abused. The therapist is therefore arguably predisposed to confirm what he or she has been told. We conclude that the nature of the relationship between a therapist and a child client has a negative impact on the trustworthiness of the hearsay statement. We further conclude that, in general, the circumstances in which a therapist hears a child’s statement about sexual abuse are not such that a hearsay statement by the therapist will possess circumstantial guarantees of trustworthiness.
Among the factors listed in J. C. E., 235 Mont. at 274, 676 P.2d at 315, concerning “the statement itself,” is whether the statement was volunteered spontaneously. Statements to a therapist are not made spontaneously, but are made in response to questioning, whether direct or indirect. Another factor listed in J. C. E., 235 Mont. at 274, 767 P.2d at 315-16, is “the suggestiveness of prior statements by the witness ... .” In order to elicit a story of sexual assault from a child, a therapist may often resort to leading questions. Inherent in this type of suggestive questioning is the danger of planting the idea of sexual abuse in the mind of the child.
In analyzing these factors, we conclude that only in an extraordinary case will hearsay testimony by a therapist concerning the *416identity of the perpetrator or the nature of the abuse possess sufficient circumstantial guarantees of trustworthiness to be admissible into evidence. We hold that hearsay statements of a child victim of sexual abuse who does not testify at trial will, in general, not be admissible -under Rule 804(b)(5), M.R.Evid., through the child’s therapist. Nor will the hearsay statements of a child victim of sexual abuse who does testify at trial generally be admissible under Rule 803(24), M.R.Evid., through the child’s therapist.
In sum, the hearsay statements about the assaults were improperly admitted into evidence in this case. Their admission into evidence constituted reversible error. We emphasize that this ruling does not prevent an expert witness such as Sandi Bums from testifying, after a proper foundation has been laid, as to the characteristics of children who have been sexually abused or as to whether a particular child displays those characteristics. It also does not prevent such an expert from testifying under another hearsay exception such as excited utterances or res gestae, depending upon the circumstances.
III.
Did the District Court err in granting the jury’s request to have the testimony of an alleged victim read to it after the case had been submitted to the jury?
During deliberations, the jury asked the District Court to let it review Robby’s testimony. The jury’s written request to the court stated, in part, ‘We would like to review [Robby’s] testimony on the witness stand. We feel that we need all of [Robby’s] testimony ... to compare with other testimony!”
The District Court summoned counsel for both sides and informed them of the request. Defendant objected to the request. The court overruled the objection. The jury was then escorted into the courtroom and Robby’s testimony was read in its entirety.
At common law, the trial court had no discretion to read a transcript of a witness’s testimony or submit testimonial materials to the jury room for unsupervised review during jury deliberations. This rale was designed to prevent an undue emphasis of the submitted materials over all other evidence in the case. Chambers v. State, 726 P.2d 1269, 1275 (Wyo. 1986).
*417Statutory law permits a court to refresh the jury’s recollection of trial testimony under certain limited circumstances. Section 46-16-503(2), MCA. The statute provides:
“After the jury has retired for deliberation, if there is any disagreement among the jurors as to the testimony or if the jurors desire to be informed on any point of law arising in the cause, they must require the officer to conduct them into court. When the jurors are brought into court, the information requested may be given in the discretion of the court. If such information is given, it must be given in the presence of the county attorney and the defendant and his counsel.”
Section 46-16-503(2), MCA.
In construing a Wyoming statute similar to the one above, that state’s supreme court stated:
“This statute does not change the common law rule against submitting testimonial materials to the jury for unsupervised and unrestricted review dining deliberations, and it does not permit trial courts to repeat large amounts of testimony just because the jury makes such a request. On the contrary, it requires that the court discover the exact nature of the jury’s difficulty, isolate the precise testimony which can solve it, and weigh the probative value of the testimony against the danger of undue emphasis. If, after this careful exercise of discretion, the court decides to repeat some testimony for the jury, it can do so in open court in the presence of the parties or their counsel or under other strictly controlled procedures of which the parties have been notified. (Footnote omitted.) The more testimony the court repeats, the greater the danger of undue emphasis. Even with the best of procedures, it would not be proper under the statute for the court to reread a transcript or replay a videotape of a witness’s entire story just because the jury wants to review all of the testimonial matter that happens to be available or because the jury wants to review the general credibility of the witness. Undue emphasis and delay would be too likely.”
Chambers, 726 P.2d at 1276.
We agree with the Wyoming court. The kind of request contemplated by § 46-16-503(2), MCA, includes an inquiry concerning a witness’s testimony as to the width of a street, the height of an object, distance, time or some other limited request, but not the entire testimony of the witness.
The instructions given to the jury before it begins deliberations should include an instruction to submit any requests for infor*418mation in writing. If the jury submits a written request that the transcript of a witness be read to them, the district court should respond in writing as follows:
“It would be error for me to furnish you with a transcript of any particular witness for the reason that in rendering your verdict, you should not give any undue emphasis to the testimony of any one witness to the exclusion of all others. Instead, you should consider all of the evidence as a whole in rendering your verdict.
“However, if you have some particular reason or point that you are trying to resolve that relates to the evidence of this witness, you may submit that question to me in written form, and I will give it consideration.”
Through this process, an inquiry concerning a witness’s testimony can be narrowed down to such subjects as the width of a street, the height of an object, distance, time or some other limited request.
In this case, the District Court abused its discretion by reading Robb/s entire testimony to the jury. The reading of the testimony prejudiced defendant by placing undue emphasis on the statement of the alleged victim to the exclusion of the testimony of other witnesses.
Reversed and remanded for a new trial.
CHIEF JUSTICE TURNAGE and JUSTICES SHEEHY and McDonough, and the honorable Leonard langen, District Court Judge, sitting for JUSTICE BARZ, concur.The following states have enacted legislative exceptions to the hearsay rule in child sexual abuse cases: Alabama, Alaska (limited to grand jury testimony,), Arkansas, Arizona, California (only for purpose of determining admissibility of defendant’s confession), Colorado, Florida, Georgia, Idaho, Illinois, Indiana, Kentucky, Maryland, Minnesota, Mississippi, Nevada, New Hampshire (limited to civil cases to recover damages on behalf of a minor child for abuse of assault), New Jersey (limited to juvenile and family law cases), New York (limited to family law cases), Ohio (limited to juvenile court), *428Oklahoma, Oregon, Pennsylvania (limited to juvenile and family law cases), South Dakota, Utah, Virginia (limited to civil cases involving child abuse and neglect), and Washington.
Of these, Arizona, Kentucky and Mississippi have declared their statutes unconstitutional on the ground that under their constitutions and state law, the judiciary, rather than the legislature controls evidentiary rules. See State v. Robinson (1987), 153 Ariz. 191, 735 P.2d 801; Drumm v. Commonwealth (Ky.1990), 783 S.W.2d 380; Hall v. State (Miss 1989), 539 So.2d 1338.
Other states have rebuffed constitutional challegnes to child hearsy statutes. See, e.g., St. Clair v. State (1990) 301 Ark. 223, 783 S.W.2d 835 (separation of powers doctrine does not preclude General Assembly from enacting child hearsy rule); State v. Ramsey (Utah 1989), 782 P.2d 480 (child hearsay statute not void for vagueness); State v. Swan (1990) 114 Wash.2d 613, 790 P.2d 610 (defendant’s right to confrontation of witness not violated by child hearsay stature).
Typical of the hearsay statues is the Washington law enacted in 1982, which provides:
“A statement made by a child when under the age of ten describing any act of sexual contact performed with or on the child by another, not otherwise admissible by statue or court rule, is admissible in evidence in dependency proceedings under Title 13 RCW and criminal proceeding in the courts of the state of Washington if:
(1) The court finds, in a hearing conducted outside the presence of the jury, that the time content, and circumstances of the statement provide sufficient indicia of reliability; and
(2) The child either:
(a) Testifies at the proceedings; or
(b) Is unavailable as a witness: Provided
That when the child is unavailable as a witness, such statement may be admitted only if there is corroborative evidence of the act.
“A statement may not be admitted under this section unless the proponent of the statment makes known to the adverse party his intention to offer the statement and the particulars of the statement sufficiently in advance of the proceedings to provide the adverse party with a fair opportunity to prepare to meet the statement.
Wash. Rev. Code § 9A.44.120 (1988).