In 1935, W. Warrick Cardozo was a young pediatrician working at Children's Memorial and Provident hospitals in Chicago under a General Education Board fellowship when, with the aid of a grant from Alpha Pi Alpha fraternity, he began one of the first studies of sickle-cell anemia--a condition in which the majority of red blood cells are crescent-shaped. He found that sickle-cell anemia is inherited. He also established that the disease strikes African Americans almost exclusively, does not cause death among all of the victims of the disease, and that not all persons whose blood contains the sickle cells actually suffer from anemia. These findings arose thirteen years before the nature and characterization of the hemoglobin abnormality that causes sickle-cell anemia was discovered and before the disease became a subject of considerable intensive research.

Born April 6, 1905, in Washington, DC, William Warrick Cardozo was the third generation in his family to attain prominence. His father, Francis L. Cardozo, Jr., was a school principal; his grandfather an educator and politician. William attended Washington public schools, then Hampton Institute in Virginia. At Ohio State University, he received an A.B. degree in 1929 and a M.D. degree four years later. He served his internship at City Hospital in Cleveland, and a residency in pediatrics at Provident Hospital in Chicago.

Cardozo entered private practice in Washington, DC, in 1937, the same year the results of his sickle-cell anemia studies appeared in the Archives of Internal Medicine. He began teaching pediatrics part time at Howard University College of Medicine, where eventually he became a clinical associate professor. He did not stop refining his own learning; in 1942 he sought and gained certification by the American Board of Pediatrics, and in 1948 the American Academy of Pediatrics granted him fellowship. His special interest later turned to children's gastrointestinal disorders.

Despite the demands of a medical practice, Cardozo contributed more than his share of public service. For twenty-four years he served the District of Columbia Board of Health as the school medical inspector. He also served on the Advisory Committee of the District of Columbia Crippled Children's Society. At Howard University College of Medicine, where he taught for many years, he founded Alpha Omega Alpha Honorary Society. On August 11, 1962, Cardozo suffered a fatal heart attack. He was survived by his wife, Julia M. Cardozo, his daughter, Judy, and five sisters.