Population trends--birth and death rates, immigration patterns, sex ratios, and life expectancies--are one of the most important issues facing the international community. These trends' relationship to the world economy, the environment, and developing countries' ability to meet the needs of growing populations is a topic appropriate for the social studies classroom. Moreover, population trends are strongly correlated with other vital issues in international relations, such as world hunger, the spread of infectious diseases, the vitality of numerous political and religious movements, and the development of democracies throughout the world. The study of population is directly linked with all of the social studies, in addition to science, technology, mathematics, and the humanities. Therefore, designing lesson plans centered on population issues is an excellent way to fuse the social studies with other disciplines and show students the connections between the social and natural sciences and the direct relevance of these sciences to their lives.