Of all of Stern’s achievements, perhaps her most lasting legacy is in the modern technology of the Pap test. She collaborated with the Jet Propulsion Laboratory (JPL) and Rosenthal, then the head cytopathologist at U.C.L.A, to apply NASA computer imaging technology to Pap screening. Stern developed a liquid-based sampling system to isolate and enrich the cervical epithelium, and helped define cellular criteria for computer programs. The work she did at JPL revolutionized Pap screening for cervical cancer, and her liquid-based sampling technique is still used in hospitals, laboratories, and clinics around the world.