A solution has been found for overpopulation! Unfortunately, this is not a reason for celebration.
This essay is another in my all-too-long series of bad ways to control population. It joins essays on genocide, the Doctrine of Discovery and gun violence.
Sperm counts are declining around the world. Fortunately, most men still have enough sperm to become fathers when they want, but that might not be the case forever. There are even predictions, if the current trend continues, that the human species will cease to exist! Just how worried should we be about declining sperm counts?
A review article suggests that the average sperm counts in European and other “western” countries has declined markedly. The overall count has declined 50 to 60% from 1973 to 2011. Another study found the same—or worse—is true for Africa. Between 1965 and 2015 they found a decrease of more than 70%! Fortunately, as you remember from biology class, only one pollywog fertilizes an egg. However fertilization requires that a crowd accompany that one lucky sperm.
I look at these studies with some concern about their accuracy. However, it seems that men truly are making fewer sperm. In addition to this decrease, genital abnormalities and testicular cancer have become more common. What is affecting men so badly? Perhaps we can learn something by consulting “man’s best friend”.
Veterinarians have studied the reproduction of a group of guide dogs for decades, and found decreases in sperm quality and increases in genital abnormalities and testicular cancer. The dogs seem to reflect the same problems as men are facing! The question is: what is causing these problems?
The vets did something that most men would object to—testicular biopsies. These little bits of tissue were tested for several chemicals with names such as “PDBE28” “PCB153” and “DHEP”. The chemicals were found in the dog food, and in the biopsy tissue, too, in levels that inhibit fertility.
These chemicals have been developed in the last few decades to promote “better living through chemistry”. They are some of a huge number of organic chemicals that have beneficial uses and have found their way into our homes—and into our bodies.
Although we may not be aware, when we bring home new furnishings, they are often treated with chemicals such as PDBE28 to decrease the rate at which they burn. These chemicals are also in building materials, vehicles and plastics—they are ubiquitous. They may have saved lives because of their fire retardant properties, but they may also have changed many lives because of their biological effects. Almost all—97%—of people in the USA have detectable levels of this group of chemicals in their blood!
The shape of these artificial molecules is similar to the shape of some hormone molecules. Hormones are chemical messengers that tell distant parts of our bodies what to do. They fit into receptors that receive hormonal molecules and activate cells. The analogy of lock and key is often used because the hormonal molecule is usually specific to certain receptors on certain cells. Because their shape is similar, endocrine disrupting chemicals fit in receptors. The disruptor can either stimulate the cell or, if the “key” gets stuck in the “lock”, the disrupting chemical can block the action of the real hormone.
Switching to women, now. Female fertility is also decreasing. The epidemic of obesity is affecting fertility, as is some women waiting too long to have children. Their bodies are also sensitive to the effects of endocrine disrupting chemicals. In a study of California women, those with high levels of PCBEs took longer to conceive a pregnancy than women with lower levels.
There hasn’t been enough written in the press about endocrine disruptors, perhaps because this subject is very complicated. Two facts that stick in my mind are that endocrine disruptors have their strongest effect when they are very, very dilute— because of their combination of stimulating and blocking effects. This means that the usual testing done by the FDA may find little risk because they didn’t dilute the chemical enough—the opposite of the usual when testing for toxicity. Indeed, endocrine disruptors may have an effect when they are equal to a pinch of salt in an Olympic-sized swimming pool!
I plan to write more about endocrine disruptors since they are so pervasive and have so many bad effects. Time will tell if these chemicals will cause a significant decrease in our population. If they do, it will be involuntary—which is tragic.
©Richard Grossman MD 2018