"The Consequences of Choosing Not to Have Children: A 100-Year Human Extinction Simulation"

1. From 8 Billion to Zero: A Warning from Live Science

An article published by Live Science on June 14, 2025, simply estimated what would happen if the world chose "zero births from today." Anthropologist Professor Michael A. Little asserts, "Very few people live over 100 years. If births stop, humanity will disappear in 100 years."livescience.com

The article first explains that "population decline starts slowly and eventually becomes a steep cliff." As the elderly pass away in turn and there is a shortage of young people, the labor force supporting food production and medical supply collapses, and civilization itself becomes unsustainable in 70-80 years.livescience.com

2. Assumed "Zero Birth" Triggers

The article cites two main causes. First is the possibility of a "pandemic that sterilizes everyone" — a scenario where a genotoxic virus or chemical contamination causes global infertility. The second is a scenario where "a full-scale nuclear war wipes out the reproductive generation." Both seem like science fiction, yet they are continuous with real discussions about nuclear deterrence and the runaway of genome editing.livescience.com

3. International Demographics and Japan's "Super Low Birthrate and Aging Society"

According to United Nations population projections, the world population is expected to peak at 10 billion in the 2080s and then begin to decline.livescience.com
However, low birth rates are becoming more acute in developed countries, with the total fertility rate falling below 1.0 in South Korea and Italy. Japan is also in a danger zone with a rate of 1.20 (2024 preliminary figures).

In Japan, the debate over the "freedom not to give birth" is heating up. Articles introducing antinatalism have also covered extreme views such as "if the pain of life outweighs the pleasure, it's better not to be born."encount.press

4. The True Feelings Reflected on Social Media: The Right to Give Birth vs. The Freedom Not to

On X (formerly Twitter) and Hatena Anonymous Diary, many voices share sentiments like "I'm glad I didn't have children" and "I can't have children because this country has no future." On the other hand, posts expressing a sense of crisis such as "society will stop functioning" and "no one will be able to pay pensions" are also rapidly increasing.anond.hatelabo.jp

On Yahoo! Chiebukuro, an ambivalent consultation titled "I'm drawn to human extinction but don't want to die myself" went viral, and the answer "a society where you can give birth with peace of mind is the real extinction avoidance strategy" gained support.detail.chiebukuro.yahoo.co.jp

5. Young People Disappear First - The Critical Point of Infrastructure and Civilization

In a world with zero births, it is not just a "reverse triangular population pyramid"; the entire young generation disappears. The professor analyzes, "If there is a shortage of those responsible for food production, logistics, and healthcare, material shortages will strike before population decline."livescience.com
According to statistics from Japan's Ministry of Agriculture, Forestry and Fisheries, the average age of core agricultural workers has surpassed 68. Even if births do not cease, the reality that food self-sufficiency is at risk due to aging alone becomes apparent.

6. Another Countdown: Male Infertility and Sperm Decline

The article cites "the rising rate of male infertility" as one of the complex factors. There are reports that the average sperm count has halved due to the impact of environmental hormones and lifestyle habits, and if reproductive ability declines at a pace exceeding advances in infertility treatment technology, a "silent birth halt" could progress.livescience.com

7. Neanderthals and "Reproductive Power"

Neanderthals are often cited in textbooks as a precedent for extinction. One of the factors for their extinction is considered to be their inferior "reproductive power" compared to modern humans.livescience.com
The point that a "social structure capable of producing and raising the next generation" was more decisive than population size provides insights relevant to the modern era.

8. The "Soft Extinction" Scenario Progressing in Japan

In recent years, the media frequently reports on the "Japanese extinction scenario." According to Cabinet Office estimates, if the total fertility rate continues to remain below 1.3, the total population will fall below 50 million by the early 22nd century. Systems that "cannot function without people," such as social security, local governance, and defense systems, will successively enter crisis zones.courrier.jp

9. Antinatalism vs. Pro-Birth - Organizing the Points of Debate

• Ethical Conflicts

  • Antinatalism argues that "life is essentially suffering" and "birth itself is harmful."encount.press

  • Pro-birth advocates counter that "reproduction is essential for societal continuity" and "life also includes happy experiences."

• Resources and Environment

  • Opinions coexist that to protect the global environment, the population should be reduced, and that technological innovation can overcome resource constraints.

• Social Systems

  • The focus for moderates is whether the costs of childcare, housing, and education can be reduced to create an environment where people who want to have children can do so with peace of mind.

10. Proposals and Prospects for "Avoiding Extinction"

1. Reducing Risks of Climate Change and Security
   International cooperation to prevent pandemics and nuclear war preemptively avoids "catastrophes leading to zero births."livescience.com

2. Promotion of Infertility Treatment, Reproductive Medicine, and Gender Equality
   Equal access to healthcare that protects reproductive capabilities for both men and women is crucial.

3. Immigration and Multicultural Coexistence
   A realistic strategy to maintain the labor population that cannot be compensated by domestic birth rates.

4. Labor Substitution through AI and Automation
   While technology alleviates the "youth shortage" in society, complete substitution is difficult.

5. Dialogue with Antinatalism
   While respecting the choice of "to have children or not," expand social support to reduce factors that make "not having children" seem rational.

11. Conclusion: Welcoming Babies or Letting Go of Civilization

The Live Science article presents not just fear-inducing scenarios but highlights the obvious fact that "civilization is supported by youth and diversity." In Japan, low birth rates and aging are already advancing a "quiet extinction," and the risk of zero births becoming a reality is surprisingly close.
Ultimately, whether to have children is a personal decision. However, without mutual support from society as a whole, it will become impossible to pass civilization on to the next generation. Whether the human species will exist on Earth 100 years from now is a crossroads we are walking right now.livescience.comanond.hatelabo.jpencount.press

References & Sources

• Live Science “How long would it take for humans to go extinct if we stopped having babies?” (2025-06-14)livescience.com

• Japanese Translation Article "If Humans Stopped Having Children..." (Archive4Kids, 2025-06-11)archive4kids.ever.jp

• ENCOUNT "Antinatalism and Declining Birthrate" (2024-10)encount.press

• Hatena Anonymous Diary "I'm Glad I Didn't Have Kids, Seriously" (2023-06)anond.hatelabo.jp

• Yahoo! Chiebukuro "Thinking About Human Extinction" (2023-11)detail.chiebukuro.yahoo.co.jp

• Courrier Japon "Foreign Media Depicts 'Extinction of Japanese'" (2018-02)courrier.jp