Global sperm count has been sinking for years

There was a time when the movie ‘children of men‘ It seemed like a fairly distant dystopia, but today science forces us to look at it with different eyes due to the great drop in birth rate that we are seeing. Although in principle it could be attributed to social issues such as difficult access to housing or one could even look at women as responsible for this. But it is becoming increasingly clear that human sperm quality is declining.

The quality is going down. In this way, it is not that we have fewer children just because we decide to have them later (which too), but that biologically our ability to father them is plummeting. The scientific evidence tells us shows in this case that between 1973 and 2018 total sperm count has fallen by 62.3%. And logically, if men have fewer sperm in general, this leads to a reduced chance of conceiving.

Although it does not stop at this data. Studies that have followed men for several years also show that the average sperm concentration has gone from 101 million per ml in the 1970s to just 49 million per ml of ejaculate today.

In a generalized way. This is not a phenomenon that is only occurring in Europe or North America, but has also been confirmed by recent studies in Latin America, Asia and Africa that are suffering the same decline.

Although the most alarming thing is not the accumulated decline that we are experiencing, but the speed. Specifically, we see that since 2000 the rate of decline has accelerated, exceeding 2.6% annually without any signs of stabilization over time.

It’s not just the culture. It is easy to blame the social changes we have experienced to justify the drop in birth rates, such as the delay in couple formation or the economic stress we are experiencing. And it is true that everything influences the birth rate, but it does not explain why semen quality is increasingly worse in our environment.

To put it in context, a 30-year-old man today has, on average, half the sperm concentration than the one his grandfather had at the same age.

Because. To understand what is happening, there are different scientific reviews that point to lifestyle like an enemy. The obesitysmoking, sedentary lifestyle or diets that have a significant presence of ultra-processed foods They destroy sperm quality. A study published in PMC in 2024 also directly links obesity to oxidative stress and hormonal imbalance to the destruction of sperm quality.

But not everything focuses on what we eat, but on what we breathe and touch in our environment. The exposure to microplasticspesticides and endocrine disruptors It is altering male hormonal production that leads to this serious problem.

New biological factors. The investigations carried out in 2025 point out two new fronts here to attack in this case. The first is paternal age, since after 35 years of age not only does sperm movement decrease but sperm DNA fragmentation increases, making it of poorer quality.

Besides, imbalance in bacteria of semen is behind many cases of infertility that we previously considered “of unknown cause.” If it is true that knowing that the pathogen called Ureaplasma is one of those responsiblecan give rise to personalized treatments.

Imminent collapse? The short answer is that we are not facing an apocalyptic scenario where humanity becomes sterile overnight, but the trend is worrying. In the event that sperm concentration continues with this downward trend, a large part of the male population could fall below the threshold of natural fertility, making assisted reproduction cease to be an option and become a structural necessity to perpetuate the species.

However, there is a species for the nuance, since a 2025 study in the US suggests that the decline may not be as pronounced in men whose fertility is already confirmed, indicating that the problem could be concentrated in specific subpopulations or closely linked to those environmental factors that we can control.

What can we do? The good news is that, unlike other genetic problems, many of these factors are modifiable. The science in this case suggests that adopting the Mediterranean diet, exercising and controlling obesity is a good way to mitigate this decline.

Images | freestocks Mohamed Hassan

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