“The human male was not a very fertile individual. Roughly one in 20 is infertile … An old lecturer of mine used to say if men were bulls [they would] all be taken out to backyard and shot,”

“In Australia, the fertility rate has fallen to about 1.77 children per couple, well below the replacement rate of 2.2.” Laureate Professor John Aitken said.

There are many factors contributing to the decline of human fertility, varying from the long-range consequences of low selection pressure on fertility to the more immediate impacts of environmental pollution and the adoption of twenty-first-century lifestyles and aspirations. These changes are sweeping across the globe and engaging every country during their individual journeys through the demographic transition into prosperity’s golden dawn. To summarise:

Social factors: there has been a cultural shift in society’s attitude towards procreation and the establishment of a family unit. In advanced, prosperous societies, the family unit is no longer a survival strategy guaranteed to ensure our security into old age. Many younger members of society no longer feel the need to breed. The concept of a life-bond through marriage is in decline and, increasingly, life is viewed as a journey to self-fulfilment rather than self-replication.

Emotional factors: intertwined with changes in attitudes towards the meaning of life us the impact of female education. One of the hallmarks of an advanced civilised society committed to gender equality is the education of women and their entry into the workforce. Two major consequences if this trend are that women are leaving it later and later to initiate a family; the average age of a first-time mother is around 30 years in many post-transition countries and since natural fertility declines from age 35 onwards, the window of opportunity to have any children at all is vanishingly small.

Secondly, women are increasingly putting their professional ambitions ahead of their family aspirations, with the result that society no longer regards childlessness as a failure but rather a conscious decision made in the understanding that motherhood is not women’s only destiny.
Demographic factors: as fertility rates fall, population age structures change. We are becoming super0 aged societies in which increasing pressure is being put on a decreasing workforce to maintain the elderly in their dotage. High rates of taxation and long working hours will inevitably mean that those of reproductive age will not have the resources, tike or energy to devote to raising a family. We are already seeing the strain that the age-care system is currently under; however as the base of the population pyramid narrows and the apex broadens matters may get much worse.

Immigration and the mass movement of human capital; advanced industrialised societies, faced with falling fertility rates and shrinking economies have traditionally turned to immigration to generate a net influx of young productive people into their communities to maintain some semblance of populations. Unfortunately, those days are rapidly coming to an end. Fertility rates are falling all over the world, including those fountainheads of humanity – Eastern Europe, Africa, India and CHina – that habitually fuelled the skilled immigration programmes that differed the world’s most prosperous economies against the gathering storms of infertility. We may have been cynical, even cruel, in our attitudes towards economic migrants. However, there may come a time in the not-too-distant future when we live to regret their absence.

Environmental and lifestyle factors: falling fertility is not just a consequence of age it is also a consequence of age it is also the result of an unhealthy Westernised lifestyle characterised by poor diet, lack of physical exercise and an overindulgence in a variety of recreational drugs. In addition, living in modern industrialised societies involves exposure to a wide range of environmental contaminants. From radiofrequency electromagnetic radiation to industrial pollutants, such as parabens, bisphenol A and phthalate esters, that impact reproductive health. The net result of all these environmental and lifestyle factors in an ongoing global decline in sperm counts and high levels of oxidative stress that impact the fertilising potential of spermatozoa, the fertilisation of eggs and the genetic stability of the germ line.

Selection pressure and evolution: An inadvertent consequence if the demographic transition means that there is no longer intense selection pressure on fertility. AS a result we are no longer selecting for the high-fertility genotypes that sustained our species during early stages of our journey through evolutionary time. Furthermore, the increasing uptake of assisted conception therapy may make matters worse by encouraging poor fertile genes to remain within the population. If conducted at scale (and in some countries up to 10% if the population are currently generated by by ART), this technology could reinforce the global decline in human fertility, necessitating the use of yet more ART to maintain population numbers in an ever-increasing spiral that will have major implications for GOvernment and national healthcare providers.

All of these factors driving down the growth of human populations reinforce each other and may ultimately contribute a trap that we shall struggle to escape. How are we going to do that?

Extract from The Infertility Trap, Laureate Professor, John Aitken