The study of human fertility occupies a central position in the study of population for several reasons. Human fertility is responsible for biological replacement and for the maintenance of the human society.

The growth of the population of the world depends entirely on human fertility. Any society replenishes itself through the process of human fertility.

Thus, in population dynamics, fertility is a positive force, through which the population expands, counteracting the force of attrition caused by mortality.

If this replacement of human numbers is not adequate that is, if the number of deaths in a particular society continues to be more than that of births, that society would face the danger of becoming extinct.


On the other hand, excessive replacement of human numbers can also create several social and political problems for a country. The process of replacement of a group through fertility is a complicated process.

Within the biological limits of human fertility, several social, cultural, psychological, as well as economic and political factors are found to operate, and these are responsible for determining the levels and differentials of fertility.

Prior to the Second World War, the approach to the study of human fertility was mainly mathematically-oriented. The social, psychological, cultural, economic and political factors in determining the levels and differentials of fertility were not accorded a proper importance.

The main reason for this limited viewpoint was that the discipline of population studies at that time was not developed to any great extent, nor was the inter-disciplinary nature of this science realised.


The dynamic character of fertility was realised when, after the Great Depression of the early 1930s, the birth rates in North- West Europe and North America (the United States of America and Canada), which were quite low till then and which had consistently registered a declining trend, started rising, stabilised themselves at higher levels and then declined.

Till that time, demographers had expected that the birth rates in North-West Europe and North America would continue to decline or would be stabilised at lower levels.

With the upsurge in the birth rates following economic recovery a phenomenon, popularly known as the “baby boom” all the population projections, based on the assumption of declining birth rates, went haywire.

Though the “baby boom” was not anticipated and caused “never-to-be forgotten embarrassment” to demographers, it brought about a realisation amongst social scientists in general, and demographers in particular.


This phenomenon of the “baby boom” also brought to light the fact that even planned families can be large and not only small, as thought earlier.

The experiences of other countries also demonstrate that fluctuations in the fertility rates of a country might take place in response to political social and economic conditions.

For instance, in Romania as a result of legalised abortions, the birth rate declined from the level of 24.2 per thousand populations in 1956 to 14.3 per thousand populations in 1966.

When, in 1966, abortion facilities were withdrawn, the birth rate shot up to 27.4 in one year, that is, in 1967 perhaps the most rapid rise in birth rate ever witnessed in one year.


According to Ronald Freedman, “this episode in Romanian demographic history is a dramatic example of the kinds of ‘natural experiments’ occurring in human fertility, most of which are not studied systematically in order to observe causes and consequences.”

In the 1960s, it was increasingly realised that the “problematic factor” in the population growth of developing as well as developed countries was the birth rate.

The growth rates of several countries at present depend on the levels of fertility and mortality, and are not much affected by international migration. In the developing countries mortality has declined considerably, and is expected to decline further.

Birth rates in these countries, however, have not declined correspondingly, with the result that these countries are experiencing an extremely rapid population growth which, in the opinion of development experts, is a threat to programmes of social and economic development.


Though the rate of population growth could be brought down through declines in birth rates, it was soon realised that all efforts at bringing down the fertility rate would be successful only if development scientists were equipped with an adequate knowledge of fertility behaviour in the context of the cultural, social, economic and political setting.

This realisation gave an impetus to the study of fertility behaviour in various developing countries. Social scientists involved in other fields such as economics, psychology, sociology and anthropology as well as biologists, started taking a great deal of interest in the field of human fertility.

Policy-makers, administrators, medical doctors and newspaper reporters have also started taking an interest in the study of fertility, mainly from the point of view of the application of such knowledge to family planning programmes, and they have also contributed to research in the field.

As a result of all these developments, there has been a great spurt in fertility studies in developing countries, especially after 1960.


The other reasons for the growing interest in the study of fertility are also worth considering. One of these is that the age structure of any population is primarily determined by fertility and that the bulges and the gaps in this age structure can have serious repercussions, with social, economic and political overtones.

The other reason is that, because of methodological development such as the sample survey method and the introduction of new techniques of fertility measurement, like cohort fertility, the study of fertility could be undertaken from various angles.

With the help of carefully designed and sharply focused sample surveys, it has become possible to study many aspects of human fertility, such as coitus, contraception, abortion, etc., which were hitherto regarded as too personal and intimate for any systematic analysis.

In fact, at present, various personal aspects of human fertility are being successfully studied in different cultural settings.