Geneticists and Race

SYNOPSIS. During the twentieth century, geneticists have dramatically changed their assessments of the biological and social consequences of human race differences and race crossing. In the first quarter of the century, most geneticists thought that human races differed hereditarily by important mental as well as physical differences and that wide race crosses were biologically and socially harmful. The period from 1925 to the outbreak of World War II saw no change in geneticists' views on hereditary mental differences between human races, but a shift to agnosticism on the issue of wide race crosses. By the early 1950s, geneticists generally argued that wide race crosses were at worst biologically harmless, but still held to earlier beliefs about hereditary mental differences between races. The final period from 1951 to the present has witnessed the shift to agnosticism on the issue of hereditary mental differences between races. The changes in geneticists' assessments of race differences and race crossing were causedby increased understanding of the complex relationship between genes and environment and by cultural changes.