However, in the late 1920s, Pearl condemned eugenics. Pearl criticized the use of race in eugenics despite conducting research that recognized racial differences. He believed that eugenics was doing the right thing badly and that human biology was eugenics done right if it consisted of reliable statistics, objectivity, a liberal social agenda, and medical affiliations. In 1927, he published the landmark article "The Biology of Superiority", which attacked the basic assumptions of eugenics. The article was the first general attack on eugenics by someone perceived as being within the movement. It also contributed to the emergence of reform eugenics and the population control movement. Pearl was an influential member of the Advisory Committee of the World Population Conference, after which Pearl helped found the International Union for the Scientific Study of Population Problems.