Reasons for the high population growth rates in the developing countries of the world include the following:
(i) Polygamous Marriage: African men believe in marrying many wives in order to give birth to many children so as to give or produce cheap labour for farming.
(ii) Child bearing was regarded as source of wealth and higher social class among members of the community.
(iii) Improvement in agriculture leading to plentiful and varied food supply
(iv) Reduction in inter-tribal conflicts and wars
(v) Knowledge of the causes of infectious diseases and how to prevent them
(vi) Better sanitation
(vii) Reduced infant mortality rate as a result of better health care
(viii) Early marriage among the vast majority of the people
(ix) Improved health services
(x) Modernisation and industrialisation make standard of living to improve.