Eugenics is a social philosophy, which advocates the improvement of human hereditary traits through social intervention by such means as discouraging reproduction by persons having genetic defects or presumed to have inheritable undesirable traits (negative eugenics) or encouraging reproduction by persons presumed to have inheritable desirable traits (positive eugenics).
Because of its normative goals and historical association with scientific racism, the western scientific community has mostly disassociated itself from the term "eugenics", which has also been deemed a pseudoscience. The most disputed aspect of eugenics has been the definition of "improvement" of the human gene pool, such as what is a beneficial characteristic and what is a defect.
An important part of research in 19th-century Eugenics was in the form of generational charts, where several families and selected groups would be analyzed in order to detect particular genetic traits. One of the methods used by evolution theorists to represent cross-generational reproduction was through concentric circles. In this eugenics diagram, Arthur Estabrook and Charles B. Davenport, a prominent American biologist, used these visual cues to chart the members of the Nam family, aiming to convey the dizzying expansiveness of degenerates' unchecked reproduction.
Source: Estabrook, Arthur E., and Charles B. Davenport. The Nam Family: A Study in Cacogenics. Cold Spring Harbor, N.Y.: Eugenics Record Office.
[UPDATE 31-JAN-08] - This description has been revised to emphasize an absolute neutrality in regards to Eugenics, which might not have been clear when it was first written.