The demographic revolution (demographic transition) is changing the reproductive strategy of the species Homo sapiens. The whole evolution of life on Earth, including social evolution since the beginning of human society, has led to this triumph of theK-strategy of reproduction. This universal revolution has a crucial importance for the present stage of human history. The cause-and-effect relationship between economic, social and demographic changes is discussed, the interpretation of changes in the mass reproductive or family behavior as primarily a direct consequence of economic, social or cultural shifts is contested. Such explanations are redundant since the main changes in demographic behavior are a response to the necessity of restor...