Sperm counts and fertility in men: a rocky road ahead

Abstract

We all exist because of our parent's fertility; yet in the grand scheme of evolution, fertility is a crucial selection factor that has determined the future of our own and many other species. By animal standards, humans have remarkably poor fertility, although we have nonetheless managed to ‘overpopulate’ the planet. However, we now face the prospect that the population of the world, and of individual countries, will begin to contract as more and more countries move below the ‘population replacement’ level for birth rates. This is the situation for the UK, the EU, and most developed and developing nations [[1]]. As a country develops in terms of public health, economic progress and education rate, so its birth‐rate drops, and this drop has been happening ever‐faster in developing countries in recent decades with the advent of improved communication and education. > One aspect that compounds the negative impact of a low sperm count is that it is also frequently associated with reduced sperm quality At face value, fewer humans on the planet sounds like an attractive prospect: for example, there will be less pressure on resources and the environment. But it will also bring unprecedented social and financial challenges as the age structure of the population bulges at the aged end rather than at the young end. The dependence of the increasingly longer‐living aged on the fewer young for financial, social and health support will create problems for modern societies the consequences of which are unknown. Equally important, there will be fewer taxpayers to provide governments with the necessary finances for running their countries. This ‘brave new world’ scenario is an appropriate way to introduce the subject of couple fertility—male fertility in particular—because it illustrates that although fertility or infertility is an issue of huge personal importance for couples and …