The defendant, Peter Catsam, appeals his conviction of sexual assault in violation of 13 V.S.A. § 3252(3). We reverse and remand for a new trial because of the improper introduction at trial of prejudicial expert testimony.
The complainant, S. S., was ten years old at the time of the alleged sexual assault. The defendant had known the complainant’s mother for about three years before the alleged incident, and had carried on an intimate relationship with her up until approximately the time of the reports by S. S. of sexual assault. The defendant had a good relationship with the complainant to the point where, according to the child’s mother, he acted in many ways like her father. Defendant would often help to put S. S. to bed and tell her bedtime stories. It was during one of these occasions that the alleged sexual assault took place.
S. S. did not report the incident until approximately six months after it allegedly occurred. She never saw a doctor concerning the alleged assault, and there was no physical evidence to corroborate her allegations.
The prosecution called three witnesses at the trial. The complainant testified about the assault, and was the only source of direct testimony about the assault since there were no other witnesses. The complainant’s mother testified that defendant had been in complainant’s bedroom trying to help her get to sleep on the night of the alleged assault. A mental health clinician testified as an expert for the State as well. The defendant testified and denied the allegations, using fabrication of the charges as his primary theory of defense.
*368 Defendant alleges three evidentiary errors below: (1) introduction of improper expert testimony on the truthfulness of child sexual assault victims; (2) improper exclusion of his cross-examination of the complainant regarding a prior sexual assault against her by a third party; and (3) improper admission of evidence of his prior sexual, assaults on the complainant.
I.
Defendant’s first claim of error is that expert testimony that children who suffer from post-traumatic stress disorder (PTSD) do not fabricate stories about sexual assault was improperly admitted. The prosecution introduced the testimony of Sharon Termini, a mental health outpatient clinician. The court found that she was qualified to give expert testimony because of her experience treating child sexual assault victims through her work as a social worker and clinician. Ms. Termini testified that, over a two and one-half year period, she had worked with approximately 300 sexually abused children. She testified that all the sexually abused children that she had worked with suffered from PTSD.
Ms. Termini testified that PTSD is a profile of a child who has been sexually abused and includes both emotional and physical characteristics. According to her testimony, children displaying symptoms of this syndrome are generally anxious, depressed, guilt-ridden, and withdrawn. She also testified that it is common with children who have been sexually abused to delay reporting the abuse.
The prosecutor then asked the expert the following question: “Based on your training and your familiarity with this syndrome, would you say that children generally tend to tell the truth about sexual abuse?” Defense counsel objected, but was overruled. The prosecutor then rephrased the question several times, but never got an answer from the expert because of repeated defense objections. Finally, the prosecutor asked: “Do children make up stories about sexual abuse as part of the syndrome that you describe?” The expert answered: “Not in my experience. No.” Ms. Termini then testified that based on her training, experience, and evaluation of the complainant, it was her opinion that the child suffered from PTSD.
The defendant does not challenge the qualifications of the expert, the admission of her testimony relating to the emotional and *369 physical symptoms of PTSD, or her opinion that the complainant suffered from the disorder. His challenge is directed instead at the expert’s opinion that sufferers of the disorder generally do not make up stories about sexual abuse. He contends that this testimony constitutes an expert opinion on the credibility of the complaining witness, which usurps the jury’s role of determining the credibility of witnesses, thereby depriving him of a fair trial.
We first address the admissibility of profile or syndrome evidence in child sexual assault cases because it is an issue of first impression in Vermont. The rule governing the admission of expert testimony provides:
If scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education, may testify thereto in the form of an opinion or otherwise.
V.R.E. 702. Courts with near unanimity have recognized that this type of expert testimony can “assist [the jury] to understand the evidence,”
id.,
introduced in a child sexual assault case.
State
v.
Lindsey,
Given the demonstrated usefulness that such evidence can have in assisting the jury to assess the credibility of the complaining child witness, we join the majority of courts that have concluded that it is within the trial court’s discretion to admit such evidence
*370
in appropriate circumstances.
1
See
Poyner
v.
State,
The challenged expert testimony, however, went beyond the psychological and emotional profile of PTSD sufferers and an opinion as to whether the testifying complainant suffers from the disorder; the expert testified regarding the tendency of PTSD sufferers to tell the truth about incidents of sexual abuse. The State argues that that testimony comes within the profile evidence rule, since it can aid the jury’s assessment of the complainant’s credibility, and does not constitute a direct comment on the credibility of the complainant. We disagree.
When viewed as a whole, the testimony of Ms. Termini was tantamount to a direct comment that the complainant was telling the truth about the alleged sexual assault for which the defendant was charged. By testifying first that sufferers of PTSD generally do not fabricate claims of sexual abuse, and then that the complainant suffers from PTSD, her testimony left one clear and unmistakable inference to be drawn: the complainant would not fabricate this allegation. The fact that the expert does not testify directly to the ultimate conclusion does not ameliorate the difficulty with the opinion on credibility. Other courts have concluded, as do we, that expert testimony that child victims of sexual abuse generally tend not to fabricate incidents of abuse is the equivalent of a direct comment on the credibility of the testifying complainant. See
Lindsey,
Once the false distinction is recognized between the challenged expert testimony in this case and an expert’s direct comment on the credibility of a complaining witness, review of the court’s admission of this evidence is simplified. Although the admission of expert testimony is within the discretion of the trial court,
Onorato,
In
State
v.
Bubar,
Furthermore, this error cannot be eradicated on the ground that it was harmless. As we noted in
State
v.
Hamlin,
While admission of this type of expert testimony might be harmless in a case in which there was ample extrinsic evidence of guilt, that is not the case here. In this case, the State introduced no physical or strong circumstantial evidence of guilt. Furthermore, the State took the opportunity in closing argument to prompt the jury to consider the expert’s testimony in assessing the complainant’s credibility. Under these circumstances, the prejudicial nature of the testimony is clear, and “it cannot be said beyond a reasonable doubt that the jury would have convicted even in the absence of the error.”
Lindsey,
While it is not our usual practice to do so, we will now discuss defendant’s two remaining arguments because they present issues that are likely to arise in a new trial. See
State
v.
Carmody,
II.
Defendant’s second claim of error is that he was improperly barred from cross-examining the complaining witness regarding a prior sexual assault 2 that had been committed upon her by a third party for which that third party had been convicted. Defendant maintains that the intended purpose of this line of questioning was to provide evidence of an alternative source of the PTSD. The trial court barred this line of cross-examination on the basis of the Rape Shield Law, 13 V.S.A. § 3255. 3 Defendant maintains that the court’s application of the Rape Shield Law vi- *373 dated his right to be confronted with the witnesses against him, as guaranteed by the Sixth Amendment to the United States Constitution 4 and Chapter I, Article 10 of the Vermont Constitution. Alternatively, he argues that the statute can and should be interpreted by this Court to allow the proffered cross-examination, thus avoiding conflict between the statute and the constitutional rights in question. We address first defendant’s statutory argument.
A.
Defendant correctly notes that a statute should, if it reasonably can, be so construed as to avoid any conflict with the constitution.
Central Vermont Railway
v.
Department of Taxes,
Even if it is assumed, for purposes of this analysis, that PTSD is a “disease” within the meaning of § 3255(a)(3)(B), other additional requirements must be met before evidence of a complaining witness’ prior sexual conduct is admissible under § 3255(a)(3). The statute allows admission of evidence which comes within the terms of the specifically enumerated exceptions only when the evidence: (1) “bears on the credibility of the complaining witness or ... is material to a fact at issue”; and (2) “its *374 probative value outweighs its private character.” 13 V.S.A. § 3255(a)(3).
While the evidence may have the minimum amount of logical relevance such that the evidence arguably “bears on the credibility of the complaining witness,”
id.,
it is still necessary that the “probative value of the evidence outweighs its private character.”
Id.
This Court held in
State
v.
Patnaude,
Defendant argues that our decision in
State
v.
Murphy,
In the instant case, the expert testimony regarding PTSD was introduced by the State to aid the jury’s understanding of particularized behavioral characteristics of child victims of sexual crimes. Thus, unlike the evidence the defendant sought to rebut in
Murphy,
this evidence was not introduced and admitted for the purpose of supporting an inference of defendant’s guilt. This
*375
Court has previously recognized that trauma syndrome evidence is not admissible to support an inference of the defendant’s guilt. See
Bubar,
Similarly, the cases cited by defendant from other jurisdictions, which have construed their rape shield statutes to allow evidence of prior sexual conduct of child victims for limited purposes, do not aid his position. In
Summitt
v.
State,
Furthermore, the probative value of evidence of prior sexual conduct of a complaining child witness depends in large part on the availability of other evidence pertaining to the issue in question. As stated by one commentator:
[I]n measuring probative worth under Rule 403 the judge cannot focus exclusively on the challenged evidence, but must look at other evidence already introduced or available to the proponent. Just as the probative worth of the evidence may decline when compared to the need for its use, so may that value increase when considered in connection with other evidence in the same or adjacent lines of proof. And on the other hand, the extent to which the value of the evidence is dependent upon other complicated lines of proof may increase the danger of confusion or the consumption of time. In short, the balancing test of Rule 403 requires that the judge consider the proffered evidence against the background of all of the evidence in the case.
22 C. Wright & K. Graham, Federal Practice and Procedure: Evidence § 5214, at 272-73 (1978) (emphasis added); see also Advisory Committee Notes, Fed. R. Evid. 403 (In determining admissibility of evidence under Rule 403, a court can balance “the probative value of and need for the evidence against the harm likely to result from its admission.”) (emphasis added).
For example, in
Black, supra,
the court interpreted the Pennsylvania rape shield law to permit, under appropriate circumstances, cross-examination of a complaining witness about prior sexual conduct to show specific bias against the defendant.
Black,
337 Pa. Super, at 556-57,
The Black court’s reasoning is persuasive and directly applicable here. Although the trial court precluded defendant’s counsel from cross-examining the complaining witness about the prior *377 sexual assault committed upon her, defendant was permitted to cross-examine the State’s expert witness about whether, in her opinion, the prior assault might have been an alternative cause of the PTSD. Under these circumstances, the probative value of whatever evidence that could have been produced through cross-examination of the complaining witness was substantially diminished by the availability of alternative means of exploring the cause of the syndrome.
On the opposing side of the balance, the proffered evidence carries with it a substantial risk of prejudicial impact which derives from its “private character.” While defendant is correct that the evidence is not offered to show unchastity, and no prejudice in the form of disrepute to the complainant’s character will result from its admission, it does not follow that a prejudicial impact of another form will not result from its admission. The proffered cross-examination of the victim would be an invasion of her privacy.
People
v.
Arenda,
B.
The defendant nevertheless contends that, as applied below, the Rape Shield Law violated his right of confrontation guaran
*378
teed by the federal and Vermont Constitutions.
7
He relies primarily on
Davis
v.
Alaska,
“ ‘The main and essential purpose of confrontation is
to secure for the opponent the opportunity of cross-examination.’ ” Id.
at 315-16 (quoting 5 J. Wigmore, Evidence § 1395, at 123 (3d ed. 1940) (emphasis in original)). Furthermore, the Supreme Court has interpreted the right of confrontation to guarantee “an
opportunity
for effective cross-examination, not cross-examination that is effective in whatever way, and to whatever extent, the defense might wish.”
Delaware
v.
Fensterer,
*379
As noted above, defendant sought to cross-examine both the complaining witness and the prosecution’s expert about the complainant’s prior sexual assault by another man in order to show a possible alternative source of post-traumatic stress disorder. Whether addressed to the complaining witness or the expert, this line of cross-examination was aimed at testing the reliability of the expert’s opinion about the cause of the syndrome. The trial court permitted full cross-examination of the expert on this issue, and defendant’s counsel argued extensively in closing argument about the relevance of these incidents to the question of the source of the syndrome. Under these circumstances, we cannot conclude that the inability to cross-examine the complaining witness,
in addition to
the expert, denied defendant his right of confrontation. Consistent with defendant’s right to confrontation, the trial court could prohibit cross-examination of the complaining witness in order to protect the victim from “unwarranted and unreasonable cross-examination into these areas,”
Arenda,
III.
Defendant next contends that the trial court erred by admitting evidence of defendant’s prior sexual relations with the complainant. Over defendant’s objection, the complainant testified that, on approximately six occasions within two years of when the charged offense took place, the defendant had sexually molested her by rubbing his penis on her leg and requiring her to touch his genitals. She testified that these acts occurred in her bedroom when her mother was either sleeping, hatching T.V., or in the kitchen. She further testified that after these incidents, the defendant told her not to tell anyone about them “or else.” According to the complainant, she did not tell anyone about what had happened on these occasions until after she had finally spoken up about the charged incident because she was afraid and embarrassed.
The admissibility of the challenged evidence is governed by V.R.E. 404(b), which provides:
Evidence of other crimes, wrongs, or acts is not admissible to prove the character of a person in order to show that he *380 acted in conformity therewith. It may, however, be admissible for other purposes, such as proof of motive, opportunity, intent, preparation, plan, knowledge, identity, or absence of mistake or accident.
The general principle of exclusion set forth in the rule is consistent with the rule previously extant in our common law that “evidence of a distinct, independent offense, though of the same kind as that charged, is not admissible” to show predisposition to commit a similar crime or propensity to engage in criminal conduct.
State
v.
Ryan,
The trial court, relying on
Huddleston
v.
State,
The rationale of the
Huddleston
decision supports the admissibility of the evidence of prior sexual acts in this case. As noted above, the controlling question at this stage is whether the evidence is relevant to an issue other than the defendant’s propen
*381
sity to commit this type of crime; “ ‘does it tend to prove any fact material to the issues in the case?’ ”
8
State
v.
Howard,
We recognize, however, as have other courts and commentators, that admitting evidence of prior sexual acts to prove a plan comes perilously close to the prohibited practice of admitting evidence of the defendant’s character to prove he acted in conformity therewith in committing the crime charged. See
State
v.
Spreigl,
*382
In order to ensure the principled application of the rule, trial courts must find, at a minimum, a clear inference of-the existence of a plan from the prior acts. At least two factors are crucial considerations in making this determination: similarity between the prior acts and the crime charged and proximity in time.
State
v.
Just,
In this case, the prior sexual contacts, although not identical, were sufficiently similar in character to the charged incident to give substantial support to an inference of a plan. All the incidents occurred at night in a bedroom; they all occurred when the defendant was purportedly telling bedtime stories; the child’s mother was always in another part of the house when the acts occurred. Most importantly, defendant always made sure to tell the victim not to tell anyone else about the incidents. When these circumstances are viewed together, we cannot say that the trial court abused its discretion in concluding that the evidence tended to establish a plan of ongoing sexual molestation.
The determination that the evidence of prior sexual acts is logically relevant, however, does not conclusively establish its admissibility.
Although relevant, evidence may be excluded if its probative value is substantially outweighed by the danger of unfair prejudice, confusion of the issues, or misleading the jury, or by considerations of undue delay, waste of time, or needless presentation of cumulative evidence.
V.R.E. 403. Once evidence of prior sexual acts is determined to be logically relevant, it is still not admissible unless it passes the balancing test of Rule 403.
Bevins,
As with evidence of prior sexual conduct of a complaining witness, the probative value of evidence of prior bad acts should be assessed in terms of the amount and strength of other evidence of guilt that is available to the prosecution. 2 J. Weinstein, Weinstein’s Evidence § 404[18], at 404-141 to 147 (1986) (citing
United States
v.
Beechum,
In this case, as in many other child sexual assault cases, there was sparse direct evidence of the crime aside from the child-victim’s testimony. There was no physical evidence; the only prosecution witness whose testimony related specifically to the incident in question was the mother, who testified to the general circumstances in the apartment on the evening when the charged incident took place. Under the circumstances, the evidence of prior acts was highly probative.
In addition, however, the potential prejudice from the admission of this evidence was extremely high. Weinstein § 404[18], at 404-149 to 150 (“All evidence of other crimes is prejudicial, but some — such as evidence of prior sexual offenses ... is probably more prejudicial than others.”). In
State
v.
Gardner,
Given the highly inflammatory nature of this type of evidence, it is essential that the court instruct the jury regarding the limited purpose for which the evidence is admitted and that the defendant cannot be tried and convicted of any offense not charged in the information. See V.R.Cr.P. 26(c);
Godfrey
v.
People,
While we may, on review, disagree with an evidentiary ruling of the trial court, such a ruling is not subject to revision unless it clearly and affirmatively appears that the trial court withheld or abused its discretion.
State
v.
Carter,
Reversed and remanded.
Notes
In addition to the requirement that the expert testimony “shed light on a subject matter that is beyond the ken of the average lay person,”
State
v.
Onorato,
E. F., a friend of the complainant’s mother, pled guilty and was convicted on July 3, 1985, of committing a lewd and lascivious act upon the complainant. The information charged E. F. with committing the alleged offense sometime between mid-August and mid-September, 1984.
The statute provides, in pertinent part:
Evidence of prior sexual conduct of the complaining witness shall not be admitted; provided, however, where it bears on the credibility of the complaining witness or it is material to a fact at issue and its probative value outweighs its private character, the court may admit:
*373 (A) Evidence of the complaining witness’ past sexual conduct with the defendant;
(B) Evidence of specific instances of the complaining witness’ sexual conduct showing the source of [sic] origin of semen, pregnancy or disease;
(C) Evidence of specific instances of the complaining witness’ past false allegations of violations of this chapter.
13 V.S.A. § 3255(a)(3).
The guarantees of the Sixth Amendment have been incorporated into the Fourteenth Amendment and therefore apply in state court proceedings.
Pointer
v.
Texas,
We note that given the limited purpose for which this evidence is admissible, it is appropriate for the court to, “upon request, . . . restrict the evidence to its proper scope and instruct the jury accordingly.” V.R.E. 105.
In
Summitt,
the court upheld the admissibility of evidence of a complaining witness’ prior sexual conduct with a third party, on the theory that it could show that “she had had other experiences which could explain the source of her knowledge of the sexual activity she described in her testimony.”
Summitt,
In
Black,
the defendant offered evidence of prior sexual conduct of the complainant with a third party to show specific bias against and hostility toward the defendant and motive to seek retribution through false accusation.
We have held that the right of confrontation, guaranteed in Chapter I, Article 10 of the Vermont Constitution, is substantively equivalent to the right of confrontation guaranteed by the Sixth Amendment.
State
v.
Sprague,
V.R.E. 401 states that:
“Relevant evidence” means evidence having any tendency to make the existence of any fact that is of consequence to the determination of the action more probable or less probable than it would be without the evidence.