Fertility, Human AIDS (Disease) -- Africa, Sub-Saharan AIDS (Disease) -- Bangladesh AIDS (Disease) Epidemiology Acquired Immunodefiecincy Syndrome Birth control Desertification Epidemiology Family size Family size--Economic aspects--Underdeveloped areas Family size--Social aspects--Underdeveloped areas Guide books Human ecology Migration, Internal Population Population policy Sexual behavior surveys -- Africa, Sub-Saharan Social surveys Underdeveloped areas