In In the Matter of the Care and Treatment of Andy Eugene Hyman, the South Carolina Supreme Court delivered a significant ruling on the admissibility of controversial scientific evidence in sexually violent predator (SVP) commitment proceedings. The Court held that penile plethysmography testing—commonly referred to as “PPG” testing—is currently too unreliable to be admitted in South Carolina courts.

The case arose after the State sought to civilly commit Andy Eugene Hyman as a sexually violent predator under South Carolina’s SVP Act. The South Carolina Office of Mental Health initially concluded Hyman did not qualify as an SVP because, although he suffered from pedophilic disorder, he did not appear likely to reoffend.

The State then obtained a second opinion from experts at the Medical University of South Carolina (MUSC), who relied heavily on PPG testing and reached the opposite conclusion.

PPG testing attempts to measure male sexual arousal by recording changes in penile circumference while a subject is exposed to sexual stimuli. The Supreme Court described the procedure as deeply invasive and scientifically controversial. Central to the Court’s decision was the overwhelming lack of standardization in how PPG tests are administered, scored, and interpreted. Different laboratories use different stimuli, scoring systems, equipment, and testing procedures, making reliable comparisons nearly impossible.

Applying Rule 702 of the South Carolina Rules of Evidence and the standards established in State v. Council, the Court concluded the underlying science had not developed enough to establish reliability. The Court emphasized that scientific evidence must be grounded in consistent and recognized methodologies before it can be presented to a jury.

The Court also found the evidence unfairly prejudicial under Rule 403 because jurors could give undue weight to the appearance of scientific certainty. Since the State repeatedly portrayed the PPG results as objective proof that Hyman posed a danger, the Court determined the improper admission of the evidence likely affected the verdict.

As a result, the Supreme Court affirmed the reversal of Hyman’s commitment and ordered a new trial without the PPG evidence. The decision places South Carolina firmly within the majority of jurisdictions rejecting PPG evidence as unreliable in forensic proceedings.

Guy Vitetta, Charleston SC