shape and subterranean character. At different times and places, the potato was accused of causing leprosy, scrofula, fever, tuberculosis, and rickets. In 1774 Frederick the Great set out to attack these superstitious beliefs. He sent a wagonload of potatoes to Kolberg to relieve a severe food shortage. After rejection of his gift by the indignant citizens, he dispatched a Swabian gendarme who convinced them that the potato was edible in the most convincing way possible: by eating one (Pyke, 1968). To overcome similar resistance in France, the government adopted a less colorful strategy. It invited the Medical Faculty of Paris to undertake an inquiry into the merits and demerits of the potato and disseminated the favorable verdict.

The example of the fork serves to remind us that even a seemingly innocent and trivial innovation may encounter resistance before more widespread (though, in this case, not universal) acceptance and incorporation into everyday life. The case of the potato is perhaps potentially more relevant to contraception because food, sex, and procreation are central concerns of all human societies. Because of this centrality, radically new products or ideas concerning these three topics are likely to arouse particularly strong reactions that often necessitate the intervention of governments or other elites.

How useful is it to pursue analogies between the spread of forks, potatoes, and contraception? To what extent can an innovation-diffusion framework help to explain marital fertility declines? These are among the key questions that will be addressed in this paper. Before doing so, however, it may be helpful to present a brief historical sketch of the role of diffusion frameworks in fertility theories.

The spread of new products or ideas between societies is such an important feature of human history that it has always formed part of broader theories of social and cultural change. Both archeology and social anthropology have been influenced heavily by diffusionism. Quantitative investigation of the diffusion of innovations also has a relatively long ancestry. It originates in the 1920s in the efforts of the U.S. Department of Agriculture to assist small farmers by encouraging them to adopt new products, such as hybrid seeds, fertilizers, and herbicides. Many of the concepts and assumptions of this early work left a profound imprint on subsequent research. These include the assumption that the new product or practice offered an indisputable benefit; an emphasis on the process of communication and a neglect of possible structural determinants of uptake of the innovation; a focus on the individual as decision maker; a concern with the roles of change agents (in this case, agricultural extension workers); investigation of the characteristics of opinion leaders, early innovators, and late innovators; and an emphasis on applied research rather than on theory building.