All knowledge about human heredity is based on genealogy, but only in the nineteenth century did genealogy become the key method for the study of heredity. Animal breeders, plant breeders, physicians, and psychiatrists all used genealogical systems to record or to reconstruct information about hereditary transmission. Genealogy, thus, was the material basis for constructing knowledge about heredity in various scientific fields. Yet, it is not only relevant as a scientific method. The use of genealogy also reflects prevailing ideas about familial and social order. Looking at genealogical practices, therefore, can tell us a lot about the political and social changes that were associated with the emergence of a science of heredity.
One aim of this project was to show how nineteenth century concepts of human heredity were expressed through and shaped by genealogical methods—or, in a broader sense, methods of data recording. Psychiatry is a particularly interesting field in this respect, since psychiatric asylums were the first institutions to record alleged hereditary phenomena regularly. While this institutional framework favored a statistical approach rather than the study of individual genealogies, pedigrees were frequently used to represent various ideas about heredity: about the familial genesis of talent and “genius,” the predisposition for delinquency or the transmission of physical abnormalities. It was not until the end of the nineteenth century, however, that genealogy was defined as an auxiliary science of biology and medicine.
The central part of the project was concerned with the redefinition of genealogy in Germany around 1900. In his influential Outlines of Scientific Genealogy (1898), historian Ottokar Lorenz defined genealogy as the bridge between historical and scientific research. Lorenz both encouraged historians to direct more attention to phenomena of heredity and called medical researchers to devote more attention to genealogical methods. In an intellectual climate characterized by the rise of biologism and eugenics, his call did not go unheard. Genealogical associations, then mainly occupied with the mere collection of family records, began to join forces with psychiatrists and other medical scientists interested in the study of human heredity.
In the years before and after World War I, plans for genealogical collections to maintain family histories and medical data flourished. Genealogical surveys were regarded as the starting point both for a scientific study of human heredity and as a means of eugenic control. Furthermore, sociologists and psychologists regarded them as a basis for understanding the formation of social groups or for examining the specific hereditary ability of individuals. And since pedigree collections could only be compiled with the help of hobby genealogists, eugenicists hoped that such enterprises might help to popularize eugenic ideas. In short, genealogy was at the center of diverse scientific and political interests and generated new scientific and political ideas. The interest in genealogy culminated under the Nazi regime, when numerous eugenic databases were created and the right to live became virtually dependent on one’s family chart. The practices of genealogy, thus, represent an important chapter in the history of biopolitics in the twentieth century.