National District Attorneys Association



Volume 17, Number 3, 2004


Limits and Lessons: The Expert Medical Opinion in Adolescent Sexual Abuse Cases

By Roger A. Canaff, J.D.1

In recent years, the opinions of medical experts in sexual assault litigation have taken on both increased importance and increased scrutiny. In appropriate cases, physicians and specially trained nurses (Sexual Assault Nurse Examiners or SANEs) can be admitted as experts and render opinions on human tissue and anatomy.2 This expert opinion often addresses the possible cause of observed injury to the vaginal area in rape cases. For instance, an expert may be able to opine that certain tears, bruises or redness to the vulva were caused by blunt force trauma. In addition, experts can also render opinions as to why injury may not have been seen in a particular case; an expert’s knowledge of the resiliency and elasticity of human tissue may help the jury to understand why no injury was observed even though a sexual assault was reported.3

These types of opinions are often accepted without objection. However, tremendous controversy has developed around the limits of medical expert testimony in cases where there is a consent defense. In such a case, observed injury to the vagina may be of interest to the prosecutor trying to corroborate the victim’s claim that the sexual intercourse was non-consensual. In the context of child abuse, this issue becomes relevant primarily in cases involving physically mature adolescent females. Even in jurisdictions where any sexual intercourse between adults and minors is prohibited, consent may still constitute the difference between a relatively non-serious crime and a much more serious felony like rape. In cases where the consent of the adolescent is at issue, relatively severe injuries observed to the vaginal area may give rise to the opinion that the intercourse was consistent with a non-consensual act. It is this possible relationship between injury and the likelihood of consent that has generated so much controversy within the medical and legal communities.

This article will examine how one state, Virginia, has addressed this controversy through its trial and appellate courts.

The Human Sexual Response Issue: Commonwealth v. Johnston

In Fairfax County, Virginia, the controversy surrounding the phenomenon known as the Human Sexual Response came to a head in a letter opinion issued by a trial judge in an adult case, Commonwealth v. Johnston.4 In the Johnston case, an experienced SANE was expected to offer an opinion as to vaginal injuries she observed by gross visualization,that is, injuries severe enough to be detected by the naked eye alone. In a pretrial motion, the defense characterized the anticipated opinion of the SANE, which was agreed upon by the prosecution. The defense characterization of the SANE’s opinion was that injuries detectable by gross visualization indicate a lack of the human sexual response (HSR). This in turn demonstrates sexual intercourse without consent. HSR, as described in the characterized opinion, is a group of automatic, immediate, and involuntary physical changes that women go through in anticipation of consensual sexual intercourse. When HSR occurs, the labia engorge with blood and change structurally to avoid injury. Since this physical process does not occur in non-consensual situations, injury is more likely to occur in a rape case than in a case of consensual sex.5

After hearing testimony on the anticipated opinion, the trial judge took the matter under advisement and allowed the attorneys to brief the matter based on the scientific research available. The judge ruled in a letter to counsel that there was an insufficient scientific basis for the opinion that consensual and non-consensual sex can be distinguished based on the concept of HSR. The judge found a basis for the phenomenon of HSR in the submitted medical literature and its relation to arousal, but did not find evidence directly linking consent, HSR, and the likelihood of injury. The SANE was allowed to testify as an expert as to certain matters, but not as to the relationship between injury to the victim and the likelihood of consent based on the phenomenon of HSR. This trial ruling sent shockwaves throughout the legal and forensic medical communities, and left many wondering how much expert testimony from SANEs was in jeopardy.6

The Johnston ruling is instructive for prosecutors in two crucial ways. First, it is imperative for prosecutors not to allow the defense to characterize a prosecution expert’s opinion. In Johnston, the opinion prepared by the defense used language that in retrospect was too strong for scientific testimony (i.e., “injury detectable by gross visualization demonstrates sex without consent”). The term “demonstrates” is simply too rigid for the non-absolute nature of medical testimony. It is perhaps arguable that there is a relationship between initial arousal, HSR and the likelihood of injury, but it is a complex concept that must be framed carefully. For example, although it was once believed that lubrication of the vaginal vault took place only as a result of sexual arousal, recent research has shown that the physical response is much more complicated.7 It is also likely that if HSR does serve to help protect from injury, it does so in the context of other concepts like partner positioning, gentleness, and other things not often seen in non-consensual intercourse.8 Whatever the science allows, the point is that the expert herself, and not opposing counsel, should be the one articulating it to the tribunal.

Second, the Johnston case stresses the importance of pretrial contact and preparation between the prosecutor and the expert. In Johnston, the expert was not told in advance that a motion regarding the reliability of the underlying science was at issue. She was asked to appear to answer questions about her expertise, and did not have time to review the proffered opinion in advance. The opportunity for the expert and the prosecutor to more carefully review the proffered opinion and discuss what was at stake might have led to a different result.

It is important to understand what the Johnston opinion did not disallow. It did not prevent SANE expert testimony altogether. It did not prevent all testimony about the phenomenon known as the human sexual response, and in fact did not address any SANE opinion about whether observed injuries were consistent or non-consistent with consensual sexual intercourse. Finally, it is important to underscore that Commonwealth v. Johnston was a trial level opinion only, not an appellate decision. A much broader appellate decision on another case soon followed Johnston, and answered many related questions about the limits of SANE testimony in Virginia at its highest appellate level.

The ‘Invading the Province
of the Jury’ Issue:
Commonwealth v. Velasquez

The Velasquez case reached the Virginia Supreme Court on two issues relevant to the limits of SANE testimony: First, the defense asserted that, even if SANEs could be considered experts, they should not be allowed to render expert opinion about the possible cause of an observed injury. This, according to the defense, would constitute the making of a medical diagnosis, and thus lie beyond the scope of nursing practice. Second, the case was appealed on the grounds that the SANE’s testimony invaded the province of the jury by rendering testimony that spoke to the ultimate issue of the case.9

The Virginia Supreme Court rejected the first argument and remanded the case back to the trial court for a new trial on the second. Regarding the first argument, the defense did not challenge the expertise of the SANE, but asserted that she was practicing medicine without a license by rendering opinions about the possible cause of injury. The court reviewed both the Virginia statutes on medical licensing and the relevant case law, and ruled that SANEs do not practice medicine when they opine about the possible or probable cause of an observed injury.10

The second issue was more problematic. No expert in Virginia can testify as to the ultimate issue in the case, but experts can express their opinion in terms of consistencies. In this case, the SANE testified, in response to two separate questions, that the injuries she observed were both “consistent with non-consensual sex” and “inconsistent with consensual sex.” These two responses taken as a whole, said the court, combined to “close the circle” and comment improperly on the ultimate issue. From the language of the case, it appears that an opinion expressing the consistency of a certain injury with consensual sexual intercourse is permissible. However, an opinion expressed in such a way as to exclude all other possible causes of that injury is not.

The Limits of the Science v. the Limits
of the Law

Many things can contribute to an expert opinion about the likelihood of consensual sexual intercourse given the severity of an observed vaginal injury. Ideally, this opinion in adult or adolescent cases will be rare. No injury is seen in most cases of rape, and most physical findings that are noted are non-specific.11 It is only in the case of particularly severe vaginal injuries, still bleeding in most cases and apparent to the naked eye, that a prosecutor should expect an experienced expert to consider rendering an opinion about the likelihood that such injuries occurred during consensual sexual intercourse. Additionally, the science underlying these opinions is not settled. HSR is a complicated physical phenomenon that is not fully understood, and among medical experts, there are differing schools of thought as to what HSR can say about the relationship, if any, between injury and consent. SANEs and other medical experts must familiarize themselves with the limits of the known science in framing opinions.

Prosecutors must know what their state law allows regarding the limits of medical expert testimony in this area, and must be prepared to argue the issue in a pretrial motion if the law is unclear. It is crucial for the prosecutor and the expert to work together to determine how these respective limits will form medical testimony. Cases from jurisdictions such as Virginia may be of value as persuasive authority in other jurisdictions where the issue has not yet been litigated. Other jurisdictions have taken up similar issues related to SANEs, particularly their status as experts, with generally favorable results for the prosecution.12


Child sexual abuse prosecutors working with adolescent victims may have the occasion to elicit an expert opinion regarding the severity of vaginal injuries in a small but important subset of cases. In a case where consent is a central issue, experienced SANEs or other medical experts may be willing to offer an opinion as to the severity and acuteness of the injury in relation to the defendant’s claim that the sexual intercourse was consensual. The opinion must be conservative, stated in terms of consistencies, and very carefully constructed. Preparation with the expert and a thorough understanding of the laws of evidence will ensure that prosecutors attempting to elicit these opinions will do so fairly, correctly, and effectively.


1 Senior Attorney, National Center for Prosecution of Child Abuse.

2 See Canaff, Roger, Pediatric Sexual Assault Nurse Examination: Challenges and Opportunities for MDT’s in Child Sexual Abuse Cases, Update, Vol. 16, No. 9.

3 Id.

4 Commonwealth v. Johnston, 2000 WL 33177221 (November 1, 2000).

5 Id.

6 See, e.g., Jackman, Tom, “When Rape Is In Question, So Are Nurses’ Answers,” The Washington Post, Monday, April 2, 2001, pg. B01.

7 See Giardino, Angelo, MD, et al, Sexual Assault: Victimization Over The Lifespan, A Clinical Guide, G.W. Medical Publishing 2003, p. 234, “Lubrication.”

8 Id. p. 230-237 “Research on Injuries in Sexual Assault.”

9 Velasquez v. Commonwealth, 263 Va. 95, 557 S.E.2d. 213 (2002).

10 Id. at 102, 103, 216, 217.

11 Giardino, Angelo, M.D., et al, supra note 8.

12 See, e.g., Griffin v. State, 531 S.E.2d 175, 180 (Ga. Ct. App. 2000)(SANE with over 20 years experience in obstetrics and gynecology, specialized training in examining victims of sexual assault, and 100 previous examinations qualified as an expert in the field of sexual assault examination); Cevez v. State, 2000 WL 1618459 (Tex. Ct. App. 2000)(unpublished)(SANE allowed to testify regarding causation when the SANE took a 48 hour course over three weekends on sexual assault, performed three supervised examinations, conducted 20 independent examinations, and periodically met with other nurses and a doctor to review cases).