London: Men trying for fatherhood receive a wealth of lifestyle advice on how best to boost their fertility wear loose-fitting underpants, avoid hot baths, get a good night’s sleep, and steer clear of junk food. It is advice backed by research including a study in June, led by Harvard University in the U.S.
Which found that men (the average age was 19) who ate the reddest and processed meat, sugary drinks, and starchy carbohydrates had the lowest average sperm counts. On average, these were 25.6 million lower than those who ate the least processed food. (A count of 39 million sperm is normally considered the minimum required to conceive naturally.)
However, scientists are now uncovering a far more worrying truth. It seems that for most men suffering infertility from a low sperm count, the damage was done decades earlier — while they were still in the womb.
Evidence increasingly shows that the delicate processes involved in forming their reproductive organs can be disrupted in the early months of pregnancy, inflicting damage that can harm their chances of fatherhood. Moreover, new studies suggest that this not only sends their sperm counts plummeting, it also significantly raises men’s risk of serious illnesses such as cardiovascular disease and cancer in later life.
Male fertility is clearly in crisis. A comprehensive review of evidence in 2017, based on 7,500 studies, shows that sperm counts among Western men have more than halved over the past 40 years. The review authors, from the Hebrew University of Jerusalem in the journal Human Reproduction Update, warned that the decline shows ‘no evidence of abating’.
In the UK, around one in ten men of all ages suffers from infertility (defined as unsuccessfully attempting pregnancy for a year or longer), according to research from the London School of Hygiene and Tropical Medicine published in the journal Human Reproduction in 2016.
Other studies indicate that as many as one in five men under 35 has a low sperm count. British infertility experts are now beginning to explore the root causes of this 21st-century plague. Already much of the evidence points to chemical pollutants in the air, water, and ground around us as the prime culprit.
There is also evidence that parents’ pre-conception lifestyles may affect their children’s health, and even their fertility, and that the problems may be passed on through the parents’ sperm or eggs by changes in the DNA (known as epigenetic changes).