Is male fertility declining?

In short the science says that male fertility is declining. Numerous studies have demonstrated a significant decrease in male fertility globally over the last several decades. Several factors are contributing to this decline, including lifestyle choices, environmental toxins, and medical conditions.

What's in this article

What do the studies show?

Studies show that sperm is trending lower

The most comprehensive analysis of the trend comes from a 2017 study published in the journal “Human Reproduction Update.” Researchers reviewed 185 studies involving almost 43,000 men who provided semen samples from 1973 to 2011. They found a 52.4% decline in sperm concentration and a 59.3% decline in total sperm count in men from North America, Europe, Australia, and New Zealand.

Why is this happening?

Several hypotheses have been proposed to explain this decline.

  1. Modern lifestyle choices, such as smoking, alcohol consumption, poor diet, and lack of exercise, have been linked to reduced sperm quality. Studies have found that these factors can negatively affect sperm concentration, morphology, and motility, all critical parameters in male fertility.
  2. Exposure to environmental toxins, including pesticides, endocrine disruptors, and heavy metals, has also been implicated in the decline. These toxins can interfere with normal hormone function and directly damage germ cells that produce sperm.
  3. An increase in medical conditions such as obesity, diabetes, and urological conditions has been correlated with reduced fertility. Obesity, for instance, is linked to hormonal imbalances that can impact sperm production, and diabetes can lead to erectile dysfunction and ejaculation problems, thus impacting fertility.

Despite the seemingly grim picture, it’s important to note that individual fertility varies greatly, and a decrease in average sperm count doesn’t equate to infertility for all men. Nonetheless, the trend is concerning and suggests that action may be necessary, especially given the potential links between decreased sperm count and other health issues such as testicular cancer and reduced lifespan.

What happens next?

We’re still identifying the exact causes

Continued research into the causes and potential remedies of declining male fertility is critical. Possible solutions could include lifestyle modifications, changes in public health policy to reduce exposure to environmental toxins, and improved treatments for conditions that may affect fertility. Meanwhile, further studies are required to validate and expand on the current findings, to help better understand the implications of this concerning trend.

A growing body of research is trying to understand the complex dynamics of male fertility decline, its causes, and consequences.

A landmark study conducted by Swan et al. (2000) established that sperm concentration had declined by 1.5% per year in the US and by 3.1% per year in Europe from 1938 to 1990. The results were similar even after controlling for variables such as age, abstinence time, and selection of the population.

Later, a 2012 study published in the British Medical Journal (BMJ) found a steady decline in sperm quality, with 1 in 5 young men having low sperm count, thereby potentially impairing their fertility. This study, involving 5000 men in France, is noteworthy as it is the first study conducted in a general population and not based on men attending fertility clinics.

An alarming finding of these studies is that the rate of decline does not seem to be slowing. In a 2017 meta-analysis of 185 studies of almost 43,000 men, a significant decline in sperm counts was observed among men from Western countries, with no sign of ‘leveling off’ in recent years.

On the environmental front, a 2019 study published in JAMA Network Open, by a team of researchers at the Icahn School of Medicine at Mount Sinai, found a strong correlation between exposure to PM2.5 (fine particulate air pollution) and abnormal sperm shape and size. These findings provide further evidence of the environmental impact on male fertility.

Taken together, these studies highlight a substantial decline in male fertility. However, it’s important to note that most of this research relies on observational studies, which can establish trends and correlations but not causality. Nonetheless, these findings are certainly cause for concern and warrant further investigation into potential causes and solutions.

Check our latest reviews