Population growth remains rapid in many poor countries. For example, the population of West Africa is expanding at an annual rate of 2.6 % and is expected to more than quadruple in size by the end of the century. The projected addition of one billion people to the region’s current population of 320 million is an obstacle to development and makes it difficult to be optimistic about the future of this and other regions with similar demographic and socio-economic conditions. There are several reasons for concern. The main factors that importance following are: