The paper presents the findings of the latest stage of a prospective medical-and-sociological monitoring of cohorts of families; its goal is to trace the development of child health. The monitoring is carried out in the Vologda Oblast by the Institute of Sodo-Economic Development of Territories of the Russian Academy of Sciences since 1995 and receives support from the Department of Health Care of the Vologda Oblast. The monitoring shows real-time dynamics of children's health and development and reflects the dependence of these changes on the factors that influence them. Specific examples show how factors such as parents' lifestyle, the environment in which children are brought up, financial welfare, medical and other health-related activities, diet and nutrition, housing and environmental conditions influence children's health. Over the past 20 years, the Russian Federation has undergone fundamental changes that affected the most important aspects of social life: Russia's political and economic structure changed; the country experienced two socio-economic crises and implemented intensive reforms in the key sectors (education, health care, housing-and-utilities sector, and agriculture). Changes in the economy have had a significant impact on public health and on children's health in the first place. On the basis of these studies, the authors show positive trends in the reforms of the economy in general and the social sphere in particular; these trends are reflected in the living conditions of families with children, in the level of health satisfaction, in the state of health of newborns, and in obstetric care statistics. The paper presents major factors contributing to the presence of functional abnormalities in the health of newborns (quality of living conditions in families, income level, health status of the mother, maternal smoking).