In medical training, doctors were taught that Black patients have lower lung capacity than white patients, a claim based on evolutionary arguments. Spirometry, a test that measures lung capacity, has included a race correction that reduces the expected normal value for Black individuals by 10 to 15 percent. The practice originated from research with roots in 19th‑century slave studies, according to a review of historical medical literature. After becoming a pulmonary physician, Aaron Baugh observed that the correction was inaccurate and contributed to misdiagnoses. He said the test is used for diagnosing disease, hiring decisions, disability determinations and treatment selection, and errors can affect many patients. A collaboration between the Reveal podcast and the New England Journal of Medicine podcast examined the issue and found that the test continues to be employed in hospitals nationwide. The findings raise concerns about health disparities and the need for revised clinical guidelines. Further study and policy review are expected.