while others are too expensive or unsatisfactory in some other way. This underlying discontent with current contraceptive technology is at the heart of repeated calls for expanded research to develop new forms of contraception (Chapter 9).
It is also important to emphasize here that the committee considers knowledge about methods of birth control, as well as access to them, to be basic requirements for effective contraceptive use. This view is consistent with observations about such other preventive interventions as prenatal care and immunizations, where the point has been made that both knowledge and access are necessary preconditions to use (Institute of Medicine, 1994, 1988). However, as subsequent material suggests, these basic elements, on their own, may not be enough to produce careful and consistent use of contraception; they are necessary but may not always be sufficient to prevent unintended pregnancy. Put another way, it is unreasonable to expect widespread, careful use of contraception in the absence of basic knowledge and access to services, but this does not mean that when such pieces are in place good contraceptive use is guaranteed. This perspective is developed in more detail in Chapter 6.
One of the explanations most often given for unintended pregnancy is that men and women, especially those who are teenagers, are poorly informed about contraception and related topics in reproductive health. Accordingly, this section considers that explanation and also addresses the skills needed to use many reversible methods. The section concludes with a discussion of school-based education and information about contraception.
Individuals learn about contraceptive methods, including their risks and benefits, as well as how to use them, from a wide variety of sources: friends and family, the electronic and print media, health professionals and the educational materials that they distribute, such institutions as schools and colleges, and numerous community resources. Unfortunately, few data are available to assess carefully the content and quality of the information provided in each of these settings. There are data about school-based sex education programs, summarized later in this chapter, but little on the content and quality of information available through the adolescent grapevine, for example. Few studies have addressed the education that parents offer their children about contraception, although some studies suggest that parents often do not discuss contraception with their children and that, in any event, such communication may not exert much of an effect on