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Pollution is causing a male fertility crisis, suggests a growing body of evidence. The quality of sperm has plummeted.
“We can take care of you. No problem. We can help you,” the doctor told Jennifer Hannington. Then he turned to her husband, Ciaran, and said: “But we can’t do much for you.”
The couple lives in Yorkshire, England, and has been trying to have a baby for two years. They knew that conception could be difficult because Jennifer suffers from polycystic ovary syndrome, a condition that can affect fertility. What they didn’t expect is that there would be trouble on Ciaran’s side as well.
Tests revealed low sperm count. And, what’s worse, the treatment is considered more difficult than Jennifer’s – in some cases, even impossible.
Ciaran Hannington still remembers his reaction: “Shock. Grief. I was in complete denial. I thought the doctors had made a mistake.”
A male infertility It is responsible for about half of the cases infertility and affects 7% of the male population. But it is much less discussed than female infertility, in part due to existing sociocultural taboos.
For most men with fertility problems, the causes are still unexplained and the stigmatization means that many of them suffer in silence.
Studies indicate that this may be a growing problem. Several factors, such as pollution, have been shown to affect men’s fertility and, specifically, sperm quality.
Potentially, this growth can have immense consequences for individuals and for society as a whole.
Hidden fertility crisis?
The world’s population has increased dramatically over the past century. Just 70 years ago, there were only 2.5 billion people on Earth. And by 2022, the world’s population will reach eight billion people.
But the rate of population growth has slowed, mainly due to social and economic factors. Birth rates around the world are hitting record lows. More than 50% of the planet’s population lives in countries with a fertility rate below two children per woman. This results in gradual reduction of the population of these nations if there is no immigration.
Reasons for declining birth rates include positive developmental factors such as greater financial independence for women and the control of your reproductive health.
On the other hand, studies indicate that, in countries with low fertility rates, many couples who would like to have more children are prevented by socioeconomic reasons, such as lack of support for families.
Likewise, there may also be a reduction in a different type of fertility known as fecundity – the physical ability to produce offspring. In particular, studies indicate that all spectrum of reproductive problems in men is increasingincluding reduced sperm counts, lower testosterone levels, and increased incidence of erectile dysfunction and testicular cancer.
“Sperm cells are extraordinary cells”, according to gynecologist Sarah Martins da Silva, specialist in reproductive medicine at the University of Dundee, in the United Kingdom.
Seemingly small changes can have powerful effects on these highly specialized cells, particularly their ability to fertilize eggs.
“Usually, when you have less than 40 million spermatozoa per milliliter of semen, you start having fertility problems”, according to professor of epidemiology Hagai Levine, from the Hebrew University of Jerusalem, in Israel.
Levine explains that the sperm count has a strong relationship with fertility. A higher sperm count does not necessarily mean a greater chance of conception, but below the 40 million/ml threshold, that chance drops quickly.
In 2022, Levine and his collaborators published an analysis of global sperm count trends. The study demonstrated that the sperm counts They fell, on average, 1.2% per year between 1973 and 2018, from 104 to 49 million/ml.
And since the year 2000, the speed of decline increased to more than 2.6% per year. Levine argues that this acceleration can be caused by epigenetic changes – changes in the way genes work, caused by environmental factors or lifestyle.
Another analysis also indicates that epigenetics may be one of the factors for sperm changes and male infertility. “There are signs that this could be cumulative over generations,” he says.
The idea that epigenetic changes can be inherited over generations is controversial, but there is evidence to suggest that it might be possible.
Individual lifestyle changes may not be enough to stop the decline in sperm quality. But mounting evidence indicates that there is a much broader environmental threat: toxic pollutants.
toxic planet
Scientist Rebecca Blanchard’s investigation focused on substances found in plastics, flame retardants and common household products. Some of these substances have been banned but still remain in the environment or in older products.
Blanchard’s studies revealed that these substances can disrupt our hormonal systems and impair the fertility of dogs and men.
DNA fragmentation in spermatozoa designates lesions or breaks in the spermatozoon’s genetic material. Its impact can go beyond conception – the greater the levels of DNA fragmentation, the more cases of miscarriage occur during pregnancy.
Blanchard’s findings confirm other studies demonstrating the impairment of fertility caused by substances found in plastics, household medicines, in the food chain and in the air. They harm men, women and even babies.
Climate change can also harm male fertility. Several animal studies indicate that sperm are especially vulnerable to the effects of rising temperatures.
Heat waves have been shown to damage sperm in insects, and similar impacts have been seen in humans.
A 2022 study concluded that heat – due to global warming or while working in high-temperature environments – impairs sperm quality.
