dissenting:
The majority today holds that the trial court did not err by admitting testimony relating to post-traumatic stress disorder (PTSD) in a rape case to prove lack of consent. I disagree.
I believe that the Frye test,1 which this Court adopted in Reed v. State, 283 Md. 374, 389, 391 A.2d 364 (1978), as the standard for evaluating the admissibility of the results of a scientific process or technique, is applicable in the present case. Moreover, the testimony at issue does not meet that test for admissibility because the presence or absence of post-traumatic stress disorder is not “generally accepted” in the relevant scientific community as reliable evidence as to whether a rape in the legal sense occurred or whether a woman consented to a particular act of sexual intercourse. Testimony about PTSD is therefore inadmissible, under the Frye test, for that purpose.
Even if the Frye test were inapplicable, I would decide, nonetheless, that the trial court abused its discretion in the present case by admitting Dr. Spodak’s testimony. The dangers of unfair prejudice and confusion of the issues arising from his testimony drastically outweighed whatever minimal probative value it may have had. In addition, Dr. Spodak impermissibly invaded the province of the jury by expressing an opinion about the credibility of the complaining witness’s testimony.
*112I.
A.
Courts which have addressed the admissibility of expert opinion testimony about rape trauma syndrome or post-traumatic stress disorder in a rape prosecution to show lack of consent have generally considered, as a threshold question, whether the basis of the opinion is accepted as accurate and reliable in the scientific community. Most have applied the standard set forth in Frye v. United States, 293 F. 1013 (D.C.Cir.1923), and adopted by this Court in Reed v. State, supra, 283 Md. at 389, 391 A.2d 364. This standard requires, where an expert opinion is based upon a new scientific process or method, that the scientific process be shown to be “generally accepted as reliable within the expert’s particular scientific field” before his opinion may be received in evidence at trial. People v. Bledsoe, 36 Cal.3d 236, 203 Cal.Rptr. 450, 457 n. 7, 681 P.2d 291, 298 n. 7 (1984); State v. Marks, 231 Kan. 645, 647 P.2d 1292, 1299 (1982) ; State v. Taylor, 663 S.W.2d 235, 239-240 (Mo.1984). See State v. Huey, 145 Ariz. 59, 699 P.2d 1290, 1294 (1985) (quoting State v. Marks, supra)) State v. Saldana, 324 N.W.2d 227, 229-230 (Minn.1982) (evidence of rape trauma syndrome “may not be introduced ‘until further evidence of the scientific accuracy and reliability of syndrome or profile diagnoses can be established.’ ”) But see State v. Liddell, 685 P.2d 918, 923 (Mont.1984).
The State contends that the Frye test does not apply because post-traumatic stress disorder is a “mental disorder ... not a scientific test, technique or process” and that Frye “applies to tests or techniques used primarily to measure or identify something.” (State’s Reply Brief, p. 3). I do not agree.
In State v. Collins, 296 Md. 670, 679-681, 464 A.2d 1028 (1983) , we applied the Frye test to expert testimony based on a witness having been hypnotized. This Court agreed with the reasoning of the Supreme Court of Minnesota in *113State v. Mack, 292 N.W.2d 764, 768 (Minn.1980), where it was said:
“Under the Frye rule, the results of mechanical or scientific testing are not admissible unless the testing has developed or improved to the point where experts in the field widely share the view that the results are scientifically reliable as accurate. Although hypnotically-adduced ‘memory’ is not strictly analogous to the results of mechanical testing, we are persuaded that the Frye rule is equally applicable in this context, where the best expert testimony indicates that no expert can determine whether memory retrieved by hypnosis, or any part of that memory, is truth, falsehood, or confabulation — a filling of gaps with fantasy. Such results are not scientifically reliable as accurate.”
In the instant case, expert testimony that the complainant Mrs. Lemon suffered from post-traumatic stress disorder (PTSD) and that, in the expert’s opinion, the rape described by Mrs. Lemon caused the trauma, was offered to show that she did not consent to intercourse and that a rape, in the legal sense, occurred.
Although, like the testimony at issue in Collins, this testimony “is not strictly analogous to the results of mechanical testing,” the policy reasons behind the Frye rule are equally applicable in this context. In Reed v. State, supra, the Court set forth the policies underlying the Frye test. We said that “[f]airness to a litigant would seem to require that before the results of a scientific process can be used against him, he is entitled to a scientific judgment on the reliability of that process.” 283 Md. at 385, 391 A.2d 364. Accordingly, “laymen should not on a case by case basis resolve a dispute in the scientific community concerning the validity of a new scientific technique.” Id. at 387, 391 A.2d 364. This would lead to inconsistent decisions in different cases. The Frye standard avoids this problem.
In addition, by not admitting evidence of a particular process or technique until it is generally accepted in the *114scientific community, courts avoid distracting the trier of facts from the merits of the case with a protracted battle of experts over the reliability of a particular process or technique which “may well degenerate into trials of the technique itself.” Reed v. State, supra, 283 Md. at 388, 391 A.2d 364. Because these policy considerations apply equally to expert testimony concerning post-traumatic stress disorder introduced to prove lack of consent in a rape case, I would hold that before a trial court may receive such evidence it must be shown that evidence of post-traumatic stress disorder is generally accepted by psychiatrists and psychologists for this purpose.
B.
The majority correctly indicates that “[tjhere is no issue in this case over the fact that psychiatrists and psychologists recognize PTSD as an anxiety disorder.” The recent psychiatric manual, American Psychiatric Association, Diagnostic and Statistical Manual of Mental Disorders 236-238 (3d ed. 1980), lists four diagnostic criteria for the disorder: 1) the existence of a recognizable stressor that would evoke significant symptoms of distress in almost everyone, 2) reexperiencing of the trauma, as in dreams and intrusive recollections, 3) numbing of responsiveness to or reduced involvement with the external world, and 4) at least two of the following symptoms that were not present before the trauma: exaggerated startle response, sleep disturbance, guilt about surviving when others have not, memory impairment or trouble concentrating, avoidance of activities that arouse recollection of the traumatic event, and intensification of symptoms by exposure to events that resemble the traumatic event.
In 1974, Ann Burgess and Lynda Holmstrom coined the term “rape trauma syndrome” to describe the psychological symptoms of victims of sexual assault. Burgess & Holmstrom, Rape Trauma Syndrome, 131 AmJ.Psychiatry 981 (1974). Rape trauma syndrome is recognized as a sub-category of post-traumatic stress disorder in which the trigger*115ing trauma is rape. Rape and Sexual Assault: A Research Handbook 46-50 (A. Burgess ed. 1985); Martin, Warfield & Braen, Physician’s Management of the Psychological Aspects of Rape, 249 J. A.M.A. 501 (1983).
Courts discussing the admissibility of testimony about rape trauma syndrome to show lack of consent in a rape prosecution have generally recognized that “[a]n examination of the literature clearly demonstrates that the so-called ‘rape trauma syndrome’ is generally accepted to be a common reaction to sexual assault.” State v. Marks, supra, 647 P.2d at 1299. Accord, State v. Huey, supra, 699 P.2d at 1294; People v. Bledsoe, supra, 203 Cal.Rptr. at 458, 681 P.2d at 299; State v. Taylor, supra, 663 S.W.2d at 237. See A. Burgess & L. Holstrom, Rape: Crisis and Recovery 35-47 (1979); E. Hilberman, The Rape Victim 33-40 (1976); S. Katz & M. Mazur, Understanding the Rape Victim: A Synthesis of Research Findings 215-231 (1979); Martin, Warfield & Braen, supra, at 501; T. McCahill, L. Meyer & A. Fischman, The Aftermath of Rape 73-77 (1979); S. McCombie, The Rape Crisis Intervention Handbook 124-126 (1980); Rape and Sexual Assault, supra at 46-50.
The Supreme Court of Kansas held that rape trauma syndrome satisfied the Frye test because it “is generally accepted to be” a common reaction to sexual assault. State v. Marks, supra, 647 P.2d at 1299. Other courts, however, have recognized that the relevant question is whether the presence of rape trauma syndrome in the alleged victim is generally accepted by psychiatrists and psychologists as accurately and reliably showing that a rape in the legal sense occurred. People v. Bledsoe, supra, 681 P.2d at 299-301; State v. Saldana, supra, 324 N.W.2d at 229. See State v. Taylor, supra, 663 S.W.2d at 238. Nothing in the literature suggests that evidence of post-traumatic stress disorder or rape trauma syndrome reliably indicates that a rape has occurred. In People v. Bledsoe, supra, 203 Cal.Rptr. at 459, 681 P.2d at 300, the Supreme Court of California explained:
*116“[R]ape trauma syndrome was not devised to determine the ‘truth’ or ‘accuracy’ of a particular past event — i.e., whether, in fact, a rape in the legal sense occurred — but rather was developed by professional rape counselors as a therapeutic tool, to help identify, predict and treat emotional problems experienced by the counselors’ clients or patients. As the professional literature makes clear — and as the expert testimony in this case also reveals — because in the past women who have brought charges of rape have traditionally had their credibility or motives questioned by the police and others, rape counselors are taught to make a conscious effort to avoid judging the credibility of their clients. As one expert in the field recently wrote: ‘When a woman seeks services from a psychologist, she wants and deserves help for her problems, not judgment. Judgment is appropriate for courtrooms, not for psychologists’ offices____ [If] When a psychologist becomes judgmental, he/she has become entrapped in a major pitfall. The victim is likely to view her disclosure behavior as having been punished, to discontinue treatment and to become reluctant to seek services in the future. The obvious way to avoid this pitfall is to remember that your role is to provide services to your client, not to make a judgment about whether a “real” rape occurred or about the victim’s culpability.’ (Italics added.) (Kilpatrick, Rape Victims: Detection, Assessment and Treatment (Summer 1983) Clinical Psychologist 92, 94.)”
Because post-traumatic stress disorder “is not a fact-finding tool, but a therapeutic tool useful in counseling,” State v. Saldana, supra, 324 N.W.2d at 230, and the relevant scientific “literature does not even purport to claim” that the disorder is “a scientifically reliable means of providing that a rape occurred,” People v. Bledsoe, supra, 203 Cal.Rptr. at *117460, 681 P.2d at 301, I would hold that it is not admissible for that purpose in a criminal trial.2
II.
Assuming arguendo that the Frye test should not be applied here, the trial court nevertheless abused its discretion by admitting the testimony of Dr. Spodak. The danger of prejudice and confusion of the issues which arose from the admission of this evidence far outweighed its minimal probative value. See State v. Werner, 302 Md. 550, 556, 489 A.2d 1119 (1985); Vitek v. State, 295 Md. 35, 39-40, 46, 453 A.2d 514 (1982); McCormick on Evidence § 185 (3d ed. 1984).
Dr. Spodak’s testimony began with a lengthy explanation of the nature of post-traumatic stress disorder. He then testified that, in his opinion, Mrs. Lemon was suffering from the disorder. He stated that his diagnosis was based “for the most part” on Mrs. Lemon’s own statements about her symptoms, and he related the symptoms which she had reported. The prosecutor asked: “What would be the trauma that forms the basis of your opinion?” Spodak responded as follows:
“A The only trauma that she claims that she went through at that time was being raped. She related no other — she did say that she separated from her husband in March of 1983 and subsequent to that separation went through some depression and became sedentary and lost some weight and so on. In fact, some of that started even before the separation and she sought treatment for that and she was going along — I wouldn’t say she was recovering, but she way, you know, in treatment, and she was sort of adjusting to that whole experience when the second trauma occurred in June. After that, she definite*118ly took an emotional nosedive, if you will, and that was the only, the only trauma that she described occurring around that time.
“Q Doctor, since you in fact were aware of marital problems that she was experiencing and the fact that she was going through some sort of treatment or counseling for that, in your opinion would the breakup of the marriage of 16 years be considered a traumatic event such that it would give rise to this kind of diagnosis?
“A No. First of all, it is not the type of trauma that gives rise to this diagnosis at all. It is more of a stressful situation that can cause a stress reaction with depression and anxiety and so on, but it doesn’t cause nightmares and flashbacks and avoidant behavior and being uncomfortable around young males and so on. So, for starters, it just doesn’t account for this kind of reaction, and it certainly would be most unusual, if it were to occur at all, to occur three months down the road. If it was going to occur, you would expect it right after the incident. But, as I say, it doesn’t cause this kind of reaction at all.”
On cross-examination, Dr. Spodak reiterated his opinion that no event in Mrs. Lemon’s history other than the alleged rape could have caused Mrs. Lemon’s symptoms. The defense attorney asked if Spodak would have to believe that the trauma reported by the patient actually took place in order for a diagnosis of post-traumatic stress disorder to be valid. He replied:
“A I think it is more important that the individual reporting, that is the patient or person you are evaluating, believes that it took place. But, yes, I think, the whole diagnosis is predicated on the assumption that some traumatic incident occurred, sure.
“Q So the diagnosis essentially is predicated on a belief in what the patient indicates to you took place?
“A Well, it is that coupled with, because we are constantly called upon to answer the question of whether, especially in work related incidents of trauma, are people *119malingering or not. If they describe the things that are well recognized in the textbooks as going with the condition and describe the time sequence which matches what is known about the condition, and in this case it is pretty solid evidence that they are giving you the straight scoop, if you will. So, yes, it is true that one has to presume that the trauma actually occurred. But there are a lot of other ways of in a sense checking out a story that has to do with what is known about the condition.”
In essence, Dr. Spodak testified that in his opinion Mrs. Lemon was suffering from post-traumatic stress disorder, that the rape she described caused the disorder, and that she was telling the truth.
As explained in Part I above, nothing in the relevant scientific literature indicates that the type of post-traumatic stress disorder symptoms known as rape trauma syndrome reliably proves that a rape actually occurred.3 The Court of Special Appeals correctly pointed out that, “[w]hile evidence of PTSD may be relevant to prove the victim’s resulting injury, it does not establish that rape was the trauma causing it.” Allewalt v. State, 61 Md.App. 503, 515, 487 A.2d 664 (1985). Whatever minimal probative value the evidence may have in this context is outweighed by the dangers it presents. Thus, the Supreme Court of Minnesota observed in State v. Saldana, supra, 324 N.W.2d at 230:
“Permitting a person in the role of an expert to suggest that because the complainant exhibits some of the symptoms of rape trauma syndrome, the complainant was therefore raped, unfairly prejudices the appellant by creating an aura of special reliability and trustworthiness. Since jurors of ordinary abilities are competent to consider the evidence and determine whether the alleged crime *120occurred, the danger of unfair prejudice outweighs any probative value. To allow such testimony would inevitably lead to a battle of experts that would invade the jury’s province of fact-finding and add confusion rather than clarity.”
See People v. Bledsoe, supra, 203 Cal.Rptr. at 460, 681 P.2d at 301 (quoting Saldana); State v. McQuillen, 236 Kan. 161, 689 P.2d 822, 832-834 (1984) (Schroeder, C.J., dissenting); 4 State v. Taylor, supra, 663 S.W.2d at 241-242.
Moreover, Dr. Spodak’s testimony invaded the province of the jury because he implicitly expressed an opinion about the credibility of the witness’s testimony. The majority contends that Dr. Spodak did not “attempt to express a personal opinion on Mrs. Lemon’s credibility.” I disagree. State v. Taylor, supra, involved testimony very similar to Spodak’s testimony here. Dr. Amanat, the expert witness in Taylor, testified that “he approached the victim’s disorder as rape trauma syndrome because she had been raped and because her nonverbal responses during the examination verified this information” and that “to the best of his knowledge there was nothing in the victim’s history outside the alleged rape that would have caused the intensity of her response.” 663 S.W.2d at 237. The court said that Dr. Amanat’s “entire testimony that the victim suffered from rape trauma syndrome carried with it an implied opinion that the victim had told the truth in describing the rape” and that his testimony that “he was specifically trained to evaluate verbal and nonverbal responses lends a special reliability to his opinion of the victim’s credibility.” Id. at 241. The court stated that “[t]here is a risk that the jury will regard the expert’s opinion that a victim suffers from rape trauma syndrome resulting from a forcible assault as dispositive on the issue of consent.” Ibid.
*121Similarly, Dr. Spodak’s testimony that Mrs. Lemon suffered from post-traumatic stress disorder caused by the rape she described amounts to expressing an opinion that she told the truth in describing the rape. This Court has held that “[a] witness cannot be asked to characterize the testimony of another [witness] since that is exclusively the function of the jury.” American Stores v. Herman, 166 Md. 312, 314-315, 171 A. 54 (1934). See Thompson v. Phosphate Works, 178 Md. 305, 13 A.2d 328 (1940).5 In addition, Dr. Spodak testified that his belief of Mrs. Lemon’s testimony that she was raped was based on “pretty solid evidence” and that she was giving him “the straight scoop.” This testimony, coupled with Spodak’s status as an expert, could easily have caused the jury to give Spodak’s opinion that Mrs. Lemon was telling the truth undue weight. The jury may well have considered Spodak’s opinion dispositive on the issue of consent.6
In holding that the trial court in this case did not abuse its discretion in admitting the testimony, the majority emphasizes that Dr. Spodak used only the term “post-traumatic stress disorder” and never described Mrs. Lemon’s symptoms as “rape trauma syndrome.” The majority says:
*122“[Ajvoiding that terminology is more than cosmetic. The concern with unfair prejudice is largely reduced when the terminology does not equate the syndrome exclusively with rape. In both his terminology and in his explanation, Dr. Spodak was careful to point out that severe traumas, other than rape, can produce the disorder which warrants the diagnosis of PTSD.”
The majority also contends that Dr. Spodak “did not purport to have invented a scientific test for determining consent to sexual intercourse had months earlier.” I disagree with the majority’s characterization of Dr. Spodak’s testimony. Allowing Dr. Spodak to testify that, in his opinion, the alleged victim’s symptoms were caused by the rape she described, and to testify that his opinion is based on “pretty solid evidence” that she was giving him “the straight scoop,” is extremely likely to give the jury the impression that he had a scientific method or test for determining whether the rape occurred and whether his patient was telling him the truth.
Moreover, using the term “post-traumatic stress disorder,” instead of the term “rape trauma syndrome,” does not significantly reduce the danger of unfair prejudice to the defendant. The prejudice arises primarily from allowing an expert to suggest that, because the alleged victim subjectively reports certain symptoms, she was in fact raped. Such testimony gives “a stamp of scientific legitimacy to the truth of the complaining witness’s factual testimony.” State v. Saldana, supra, 324 N.W.2d at 231 (quoting People v. Izzo, 90 Mich.App. 727, 730, 282 N.W.2d 10, 11 (1979)).
Inevitably, defendants in rape prosecutions will seek to counter the state’s PTSD evidence with testimony that the complaining witness is not suffering from PTSD or that a trauma other than rape has caused her symptoms. As the majority notes, this will “lead to issues concerning compulsory psychiatric examination of the complainant by an expert for the defense.” The majority implies that its holding that testimony as to the presence of PTSD is admissible to *123show lack of consent does not necessarily mean that testimony as to its absence will be admissible to show consent. Nonetheless, allowing the benefit of such evidence to the prosecution but not to the defense would be “fundamentally unfair and unduly prejudicial to the defendant in a rape prosecution.” State v. McQuillen, supra, 689 P.2d at 836 (Schroeder, C.J., dissenting).
On the other hand, if both the prosecution and defense are allowed to introduce PTSD evidence on the issue of consent, there is a significant danger that rape trials will degenerate into a battle of experts about the validity of PTSD evidence to show nonconsent and the presence or absence of this disorder in the complaining witness.
Because the danger of unfair prejudice and confusion of the issues from Dr. Spodak’s testimony far outweighed whatever limited probative value it may have had, and because his testimony invaded the province of the jury, I would hold that the trial court erred in admitting it.
III.
Turning to Judge McAuliffe’s concurring opinion, the distinction which he makes between admissible preliminary questions and inadmissible ultimate questions has not been reflected in the holdings of the cases admitting or excluding expert testimony on PTSD. This distinction has, however, been recognized in dicta, State v. McQuillen, supra, 689 P.2d at 829 (expert may testify as to existence of PTSD in victim, but may not state that rape caused victim’s disorder), and in a dissenting opinion, State v. McGee, 324 N.W.2d 232, 234 (Minn.1982) (because expert did not testify as to whether in his opinion rape actually occurred, his testimony should be admissible).7 Nevertheless, neither *124these opinions nor any other authority of which I am aware require counsel, opposed to an entire line of testimony, to object only to the ultimate question. The defendant should not be penalized for his counsel’s failure to foresee the position adopted by Judge McAuliffe and failure to frame the objection precisely in accordance with Judge McAuliffe’s position.
Moreover, the record in this case clearly indicates that the prosecution desired the admission of the entire line of testimony concerning PTSD, leading to answers to the ultimate questions of whether Mrs. Lemon suffered from PTSD and whether the asserted rape caused the condition. The defendant’s objection was to the entire line of testimony. The admissibility of the whole body of testimony concerning PTSD has consistently been the principal disputed issue in this case, and it was properly preserved for appellate review.
Finally, no issue regarding the adequacy of the defendant’s objection is properly before this Court. Even if the defendant’s objection were insufficient, the Court of Special Appeals decided the question concerning the admissibility of the PTSD testimony. The Court of Special Appeals has discretion to decide the merits of an issue despite the failure of a party to raise the issue at trial or to object at trial. See, e.g., Squire v. State, 280 Md. 132, 135, 368 A.2d 1019 (1977); Dempsey v. State, 277 Md. 134, 141-142, 355 A.2d 455 (1976). See also State v. Hutchinson, 287 Md. 198, 411 A.2d 1035 (1980). In such situation, this Court has consistently viewed any question concerning the adequacy of an objection at trial or preservation at trial as a separate issue under Maryland Rule 813. If it is not raised in a petition or cross petition for a writ of certiorari, and encompassed in our grant of certiorari, the matter is not before us, and we decide the case based upon our resolution of merits of the questions presented. Dean v. State, 291 Md. 198, 202, 434 *125A.2d 552 (1981); Dempsey v. State, supra, 277 Md. at 142-148, 355 A.2d 455.
Judge COLE has authorized me to state that he concurs with the views expressed herein.. Frye v. United States, 293 F. 1013 (D.C.Cir.1923).
. Such evidence may, however, be admissible on the issue of damages in a civil suit or to rebut allegations by the defendant in a rape prosecution that the behavior of the victim after the incident is inconsistent with her claim of having been raped. See People v. Bledsoe, supra, 203 Cal.Rptr. at 457, 681 P.2d at 298, and cases cited therein.
. In State v. Saldana, supra, the Supreme Court of Minnesota said that “[t]he scientific evaluation of rape trauma syndrome has not reached a level of reliability that surpasses the quality of common sense evaluation present in jury deliberations.” 324 N.W.2d at 230.
. In State v. McQuillen, supra, three judges dissented on grounds that evidence of rape trauma syndrome should not be admitted in a rape prosecution where consent is the defense and that State v. Marks should be overruled on this point.
. In Reed v. State, supra, 283 Md. at 400, 391 A.2d 364, Judge Smith in dissent, taking the position that the Frye test should not be adopted by the court as the basis for evaluating testimony regarding voiceprints, distinguished Frye from Reed. He stated that “[t]he evidence proposed in Frye was an obvious invasion of the province of the jury since the trier of fact is vested with the responsibility of determining the credibility of witnesses.” Id. at 402-403, 391 A.2d 364.
. Some jurisdictions allow expert testimony concerning the credibility of a witness in "unusual cases," State v. Saldana, supra, 324 N.W.2d at 231, citing United States v. Barnard, 490 F.2d 907, 913 (9th Cir.1973), cert. denied, 416 U.S. 959, 94 S.Ct. 1976, 40 L.Ed.2d 310 (1974), such as where the witness is a child or mentally retarded, see Commonwealth v. Carter, 9 Mass.App. 680, 403 N.E.2d 1191 (1980), aff'd, 383 Mass. 873, 417 N.E.2d 438 (1981) (whether child could distinguish reality from fantasy), or where there is evidence that the witness is insane. See generally Conrad, Psychiatric Lie Detection: The Federal Court’s Break with Tradition, 21 F.R.D. 199 (1958); Juviler, Psychiatric Opinions as to Credibility of Witnesses: A Suggested Approach, 48 Cal.L. Rev. 648 (1960).
. The distinction has also been discussed in other contexts: State v. Middleton, 294 Or. 427, 657 P.2d 1215 (1983) (expert testimony on sexually abused children); Buhrle v. State, 627 P.2d 1374 (Wyo.1981) (expert testimony on battered wife syndrome); Hampton v. State, 92 *124Wis.2d 450, 285 N.W.2d 868 (1979) (expert testimony on the reliability of eyewitness identifications).