Adobe At a time when medical researchers are under pressure to increase diversity in clinical trials, a Johns Hopkins study is sparking outrage among some physicians because of its large number of Black patients. The controversy has stoked concerns that the institution infamous for its role in the Henrietta Lacks story may have once again exploited marginalized people for medical research. The university denies any wrongdoing and instead said it was simply providing a service to its local community, which has a mostly Black population. The paper was published last fall without much notice but caused a stir on social media in recent weeks. It was a retrospective study analyzing the abilities of three specially trained nurse practitioners to perform colonoscopies, an invasive and potentially lifesaving cancer screening procedure normally done by gastroenterologists. Of the more than 1,000 patients who received screening colonoscopies from the nurse practitioners between 2010 and 2016, nearly 75% were Black.