Decreasing sperm count in men is not a new phenomenon, having first emerged some 25 years ago. However, the publication this week of research showing the sperm count of men in the western world has fallen by more than half over a period of 40 years suggests an urgent need to address the issue.
Researchers from the US and Israel used a meta-analysis technique to pool the results of 185 sperm studies carried out worldwide between 1973 and 2011. Their findings, published in the journal Human Reproduction Update, show declines of 52 per cent in sperm concentration and almost 60 per cent in total sperm count among men in North America, Europe, Australia and New Zealand. The results point to a decline in male health and fertility.
While the latest research did not explore the reasons for the fall in sperm counts, previous studies have suggested a possible link with a range of environmental and lifestyle factors. These include smoking, male obesity and stress as well as exposure to pesticides in adulthood and other chemicals during the prenatal phase of development. However, there is little solid scientific evidence to back up these putative causes.
Indeed, to put the latest research beyond doubt would require a large-scale prospective study in which the sperm counts of men were measured at age 18 and subsequently assessed at intervals throughout their lives.
A large global prospective study could also explore a trend hinted at in the current research, suggesting the decline in sperm counts in Europe and North America is not mirrored in Asia, Africa and South America.
Although separate research suggests about 15 per cent of young men in northern Europe have a sperm count low enough to impair fertility, the current study’s findings of 47 million sperm per millilitre in the average sperm count would still be considered normal by fertility clinics. The research results can fairly be described as a wake-up call. However, references to the end of humanity are premature.