There is a biological maxim that states that the fecundity of nature is proportional to the nurture, i.e, animals with high reproductive rate (fecundity) that consequently give birth to millions of young ones (like the herring fish) do not give adequate parental care (nurture) to their young ones. As a result, most of the young ones up to 80% – 90% in some cases do not grow to adulthood, and there is a natural control on population.
For man, only one or two children are born at a time (rarely three, four or more) and parental care. is intense and almost throughout life. This increases the survival rate of the human child and subsequent survival of his or her offspring in exponential proportion.
There is no limit to the reproductive capacity of humans. A man may be married to one woman or to several women. There are other reproductive relationships among young people not legally married.
Population growth is, therefore, principally the result of human reproductive responsibility (and irresponsibility). The situation is even worse in developing countries with high poverty levels, poor medical supplies and no food security.
Regions of the world with high population figures are China, India, Asia and Sub-Saharan Africa. The natural way of controlling population is to limit the number of children a couple can have; or artificially by adopting family planning programmes.