[Demographic and epidemiologic transition: problems for research]

In this paper the inherent characteristics of the demographic and epidemiological transitions are described. The main differences of the transitions between Western Europe of the 18th and 19th centuries and of the Latin American countries of the 20th century are pointed out. The demographic transition in Mexico is briefly described and the attributes that make it sui generis are indicated. It is emphasized that there has been a slowing of the rate of decline in fertility in Mexico since 1980 and some factors likely associated with this phenomenon are propounded. The different schools of thought regarding the changes of infant mortality during the transition are succinctly reviewed. The hypothesis that reductions of the birth rates induce reductions of infant mortality rates is supported by general theoretical results of the population dynamics of infectious diseases and some empirical evidences.