During the twentieth century, Austin Bradford Hill researched diseases and their causes in England and developed the Bradford Hill criteria, which comprise the minimal requirements that must be met for a causal relationship to be established between a factor and a disease. Hill also suggested that researchers should randomize clinical trials to evaluate the effects of a drug or treatment by monitoring large groups of people. In addition, Hill advocated for case-control studies, in which researchers compare a group of people with a medical condition to a group without that condition to investigate the condition's possible causes. Hill's own work with clinical trials and case-control studies helped him prove that smoking caused lung cancer. The Bradford Hill criteria have also been used to establish causal links between factors and cancer, including reproductive cancers such as human papillomavirus that causes cervical cancer.

In 1965, Austin Bradford Hill published the article “The Environment and Disease: Association or Causation?” in the Proceedings of the Royal Society of Medicine. In the article, Hill describes nine criteria to determine if an environmental factor, especially a condition or hazard in a work environment, causes an illness. The article arose from an inaugural presidential address Hill gave at the 1965 meeting of the Section of Occupational Medicine of the Royal Society of Medicine in London, England. The criteria he established in the article became known as the Bradford Hill criteria and the medical community refers to them when determining whether an environmental condition causes an illness. The criteria outlined in “The Environment and Disease: Association or Causation?” help identify the causes of many diseases, including cancers of the reproductive system.

Charles Rotimi is a researcher who studies the etiology of complex diseases and health disparities and advocates for the inclusion of greater racial and ethnic diversity in genomic repositories. In the early 2000s, Rotimi spearheaded the recruiting of African communities for participation in the International HapMap Project. As director of the Center for Research on Genomics and Global Health, or CRGGH, at the National Institutes of Health, or NIH, Rotimi led governmental research on human genetic variation and patterns of disease. Rotimi is a founding member of the Human Heredity and Health in Africa, or H3Africa, initiative, which aims to increase the representation of African populations in global genetic studies. Through his epidemiological research, leadership in advocacy groups for the support of African scientists, and his collaboration in genomic diversity initiatives, Rotimi promotes racial and ethnic representation in genetic research, especially regarding the inclusion of African people and the African diaspora.