unintended pregnancy, notably abortion and maternal mortality, and the changing requirements of the reproductive life span. "Specific needs" include sexually transmitted reproductive tract infections; lack of involvement of males in contraception; and contraceptive failure and side effects. Figure 2-1 presents this breakdown in graphic form.
In economics, "demand" has both volitional and authoritative dimensions, since it comprises the notions of desire to purchase and possess, as well as the power to do so. In classical microeconomic theory, demand has an iterative relationship with supply, a relationship that is mediated by the market, which transmits information about prices, quantities, and elasticities in each.
However, application of traditional supply-and-demand concepts to understanding the role of demand in processes of technological innovation has not been very illuminating (Lotz 1993; Mowery and Rosenberg 1982). A more rewarding perspective is offered by marketing research, which distinguishes between "needs," "wants," and "demands'' in ways that are useful for thinking about development of new medical technologies in general and contraception in particular. In one analysis, a human need is defined as "a state of felt deprivation of