Sperm Crisis and Lifestyle Habits: Unveiling the Deep-seated Reasons for Declining Male Fertility in Modern Times

In recent years, besides the hot topic of asexuality, another issue that has been very concerning to me is the increasing prevalence of sperm abnormalities among young men. Past surveys have shown that a man releases about 3 milliliters of semen per ejaculation, with each milliliter containing over 100 million sperm. This means that each ejaculation releases approximately 200 to 300 million sperm – this is the most basic estimate.

However, recent surveys have found that only about 30% of young men aged 20-29 achieve this level of sperm count. In the same survey, however, approximately 60% of men aged 60-69 achieved this. In other words, compared to older men, younger men have significantly lower sperm motility. Research by Professor Yasunori Yoshimura of Keio University's Faculty of Medicine in Japan shows that between the 1970s and 1990s, Japanese men's sperm count decreased by approximately 12%.

One milliliter of semen contains an average of about 65 million sperm in the 1970s, about 63 million in the 1980s, and only about 57 million in the 1990s-a clear decline in sperm count. Furthermore, a survey conducted by Teikyo University School of Medicine between 1996 and 1998 yielded even more alarming results. The study found that young men aged 20-29 had an average sperm count of 45.8 million, while men over 30 had an average sperm count of 84 million.

The difference is almost double. According to the WHO (World Health Organization), the sperm count necessary for natural conception is 20 million sperm per milliliter of semen. In the study above, 100% of the men around 40 years old met this standard, while only 86% of the men in their twenties met it. In fact, the number of couples experiencing infertility due to male sperm problems is indeed increasing.

The reasons for these problems may include the influence of feminized environments on the secretion of male hormones; however, I believe changes in lifestyle are also a major factor. The relationship between humans and food cannot be ignored. As the saying goes, the more scarce the food, the more children are born. Japan also experienced a large number of births during its poorest post-war period. Currently, all countries facing social problems like declining birth rates are developed nations.

From a biological perspective, when an individual has excessive nutrition, the instinct to reproduce ceases to function. Conversely, when nutritional imbalances occur due to food shortages, the individual senses a life-threatening crisis, and the instinct to preserve the species kicks in to ensure the survival of offspring. In other words, even in times of food abundance, overeating can be a contributing factor to infertility.

The same applies to the animal kingdom; male seals don't eat during mating season. My male dog also does this; whenever the female dogs in my neighborhood go into heat, my male dog suddenly stops eating. This might suggest that sperm quality can improve during fasting. Furthermore, I believe that increased meat consumption is also a contributing factor to infertility. A survey conducted by an IVF clinic in Osaka showed that 77% of men who reported frequently eating hamburgers had a high rate of sperm abnormalities.

Japan is an agricultural society that has historically relied heavily on plant-based foods. However, the Japanese diet has suddenly shifted towards that of Westerners, with meat consumption rivaling that of predominantly carnivorous, hunting-based societies. This inevitably leads one to speculate that this could be one reason for sperm abnormalities. Furthermore, for carnivores, the more offspring they have, the less food they can consume.

Conversely, for herbivores-the prey of carnivores-the species is likely to perish if they don't produce many offspring. To produce many offspring, high-quality sperm is essential; therefore, herbivores' sperm quality is likely better than that of carnivores. Thus, I believe that eating plants is more likely to produce high-quality sperm than eating meat.

Furthermore, in the survey, over 60% of the men who answered "wear jeans" reported symptoms of decreased semen volume. Stiff, poorly elastic jeans constrict the body, hindering blood circulation. Moreover, jeans press the testicles tightly against the body, raising their temperature due to increased body heat. Sperm are sensitive to heat and require a temperature lower than body temperature to be produced; therefore, wearing jeans can lead to insufficient sperm production.

In any case, the causes of male sperm abnormalities cannot be attributed to a single reason. However, it is certain that changes in modern lifestyles-the Westernization of lifestyles-have had a significant impact on sperm abnormalities in Japanese men. The increasing number of young men experiencing sperm abnormalities is also a major issue that women cannot ignore.

South Korean researchers have discovered that "semen has the effect of killing ovarian cancer cells," and studies have also shown that semen can relieve migraines in women. Considering that semen is the direct medium for sexual intercourse and is also related to women's health, abnormalities in semen are naturally one of the causes of women's physical and mental imbalances.