When an allegation of sexual misconduct surfaces in a custody case, the family court, the guardian ad litem, or one of the parents often asks for a psychosexual evaluation of the accused parent. Some evaluators have included, among their tools, a physiological test called the penile plethysmograph, or PPG, which measures a man’s physical response to a series of images and sounds and reports the result as a number. On May 13, 2026, the South Carolina Supreme Court held in In re Care and Treatment of Hyman that PPG results are generally inadmissible in judicial proceedings. The case itself was not a family court case, but the holding is not limited to the courtroom it came from. This post explains what the Court decided, why, and what it means for a psychosexual evaluation in a South Carolina custody case, whichever side of the allegation you are on.

What the Court decided

Hyman was a civil commitment proceeding under the Sexually Violent Predator Act, a matter the State brings in circuit court and that is not a family court case. The State’s evidence included the results of two PPG tests administered at the Medical University of South Carolina, and the State leaned on them heavily, telling the jury in closing that the PPG results alone were enough. The Court of Appeals reversed, and the Supreme Court, in a unanimous opinion by Chief Justice Kittredge, agreed. The Court held that PPG results are generally inadmissible in judicial proceedings unless and until the underlying science is more thoroughly developed, thus creating a more structurally sound path for a court to find PPG results are reliable and admissible. It affirmed the reversal and sent the case back for a new trial without the PPG evidence. The phrase that matters for family court is judicial proceedings. The Court did not say inadmissible in commitment trials. It said inadmissible in court.

The test the Court applied

South Carolina has its own rule for scientific evidence, and it is worth knowing because it governs every expert a custody court hears. Rule 702 of the South Carolina Rules of Evidence allows a qualified expert to testify if scientific, technical, or other specialized knowledge will assist the trier of fact. In State v. Council (1999), the Supreme Court held that before admitting scientific evidence under that rule the trial judge must find that the evidence will assist the trier of fact, that the expert is qualified, and that the underlying science is reliable, and it identified four factors for reliability: the publications and peer review of the technique; prior application of the method to the type of evidence involved in the case; the quality control procedures used to ensure reliability; and the consistency of the method with recognized scientific laws and procedures. The Court in Council expressly declined to adopt the federal Daubert standard; the South Carolina rules, and the judge as gatekeeper, do the work.

Why the PPG failed the test

The Court walked through the four Council factors and found that three of them weighed against reliability. On publications and peer review, the scientific community is polarized, and the Court observed that even the experts who believe the PPG is a valuable tool acknowledge that the test is not standardized. On prior application, the Court gave considerable weight to the fact that the state’s Office of Mental Health, the agency the statute itself designates to perform the evaluation in these proceedings, rejects the PPG as a valid or reliable assessment. On quality control, MUSC’s own procedures were described as admirable but not standard across laboratories, so the factor was at best neutral. And on consistency with recognized scientific practice, the Court found the decisive problem: the PPG varies across laboratories in at least seventeen respects, including the stimuli used, the equipment, the protocol, and the threshold at which a response is scored as significant. MUSC’s threshold was double the figure used in the literature, with no empirical justification, and MUSC ran two tests back to back with different stimulus sets, a practice no study had examined. The lack of standardization, the Court concluded, renders the test results inherently unreliable.

The Court added a second, independent reason. Even if the test were reliable, it would be excluded under Rule 403, because the PPG clothes the results of a subjective experience in supposed scientific expertise, thereby giving those results an aura of objectivity that ordinary testimony lacks. A number that purports to measure what a person is attracted to is a particularly powerful piece of evidence and difficult for a fact-finder to set aside, and its probative value did not justify that risk. South Carolina now sits with the large majority of states; the Court noted that only Washington, Illinois, and Florida admit PPG results, each under a legal framework the Court found clearly distinguishable.

What a psychosexual evaluation looks like now

A psychosexual evaluation is broader than one test. A qualified evaluator interviews the parent, takes a history, reviews records and collateral sources, and often administers standardized psychological instruments and actuarial risk tools. None of that is touched by Hyman. What Hyman removes is the PPG result: an evaluator’s report that rests on it, or an opinion that cannot be separated from it, is now open to objection in family court as it would be in any other South Carolina court. In the Hyman trial itself, the other evidence, including actuarial measures, placed the respondent within the average range for risk; the PPG number was what pushed the case over. That is the pattern a family court judge should now be alert to, and a lawyer on either side should be prepared to argue.

For the parent who has been accused, the practical point is that an evaluation is not a test you pass or fail by wire. If an evaluator proposes a PPG, your lawyer should raise Hyman before the evaluation is ordered, not after the report is written, because a report built around an inadmissible result is a report that may have to be redone. For the parent who has raised the allegation, the point is the mirror image: the case cannot rest on a number. It rests on the child’s disclosures, the timeline, the records, the forensic interview if there was one, the guardian ad litem’s investigation, and the evaluator’s clinical judgment, all of which remain admissible and all of which the court will weigh. The firm’s post on how the family court can suspend or restrict visitation explains the showing that has to be made when a parent’s contact with a child is at issue.

How the family court weighs it

The custody statute does not change. Section 63-15-240(B) requires the court to consider the best interest of the child through a list of statutory factors, and where an allegation of abuse is made, the court is weighing the credibility and weight of the evidence of that allegation like any other. A psychosexual evaluation is one input; the guardian ad litem’s report is another. The firm’s post on what a guardian ad litem’s recommendation can and cannot do explains how the Supreme Court has drawn that line. What Hyman adds is a clear rule that one category of evidence, which had a reputation for objectivity it had not earned, does not come in. A judge who has to decide whether a parent is safe for a child will decide it on the evidence that survives the rules, which is how it should be.

What to do if an evaluation is on the table

1. 01Find out exactly what the evaluator proposes to do. Ask for the protocol in writing. If it includes a PPG, tell your lawyer before the appointment.
2. 02Choose the evaluator with care, and by agreement where possible. A court-appointed or jointly selected evaluator carries more weight than one retained by a single side.
3. 03Provide the evaluator with complete records. An evaluation is only as good as the history it rests on, and gaps are read against you.
4. 04Do not discuss the allegations with the child, and do not coach the child before a forensic interview. Both are noticed and both damage the parent who does them.
5. 05Preserve everything: messages, medical records, school records, the names of anyone who witnessed the child’s behavior or statements.
6. 06Expect the evaluation to take time, and ask the court for interim arrangements that protect the child without prejudging the outcome.

Klok Law represents parents on both sides of abuse allegations in custody cases in Charleston, Berkeley, and Dorchester Counties, and works with evaluators and guardians ad litem who understand what the court can and cannot use. Call (843) 701-1695.

This article is for general information only and is not legal advice. How Hyman applies to a particular evaluation depends on the evaluator’s methods and the facts of the case. For advice about your situation, contact Klok Law at (843) 701-1695.