AbstractIn this paper we attempt to describe the general reasons behind the world population explosion in the 20th century. The size of the population at the end of the century in question, deemed excessive by some, was a consequence of a dramatic improvement in life expectancies, attributable, in turn, to scientific innovation, the circulation of information and economic growth. Nevertheless, fertility is a variable that plays a crucial role in differences in demographic growth. We identify infant mortality, female education levels and racial identity as important exogenous variables affecting fertility. It is estimated that in poor countries one additional year' of primary schooling for women leads to 0.614 child less per couple on average (worldwide). While it may be possible to identify a global tendency towards convergence in demographic trends, particular attention should be paid to the case of Africa, not only due to its different demographic patterns, but also because much of the continent's population has yet to experience improvement in quality of life generally enjoyed across the rest of the planet.