spermist

Spermist is a historical term used to describe proponents of preformationism in reproduction who posited that the male gamete, or sperm, contains a preformed miniature human or homunculus. In this view, the embryo develops within the sperm and the mother’s role is primarily nourishment and providing the womb environment, with little or no new growth occurring after fertilization. The opposing camp, the ovists, argued that the egg carries the preformed organism and that fertilization activates development.

The spermist position was popular in the 17th and early 18th centuries, following the discovery of spermatozoa by Anton van Leeuwenhoek and the ensuing debates about generation. A famous artifact of the period is Nicolaas Hartsoeker’s 1694 drawing of a homunculus positioned inside a sperm, which became a symbol of the spermist view. Spermists believed that sexual reproduction could be explained by the preexistence of a preformed being in the male gamete, with female contributions limited to nutrition, incubation, or activation.

Over time, preformationist ideas were challenged by evidence for epigenesis and by better understanding of fertilization and embryonic development. By the end of the 18th century and into the 19th, the embedded homunculus concept was largely abandoned, and modern embryology embraced the view that development proceeds from gradual formation of tissues and organs from undifferentiated cells.

Today, the term "spermist" is primarily of historical interest, used by historians of science to describe a particular phase in the study of reproduction and development.