Limiting our reproduction is the most ethical thing to do

By Jan Greguš and John Guillebaud | 11 September 2023


The following has been extracted from a paper titled “Scientists’ Warning: Remove the Barriers to Contraception Access, for Health of Women and the Planet”. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (

The human population reached 8 billion in 2022 and is still growing, and will possibly peak at 10.4 billion in 2086. Environmental science mandates that continued growth of the human enterprise on a finite planet is unsustainable and already in overshoot. Indeed, 3 billion is an evidence-based target number, for our species in competition with all non-human life-forms. We must achieve zero population growth and, ultimately, a massive decrease. Commonly, even among environmentalists who are not “population-deniers”, human numbers are seen as a given, to be adapted to rather than influenced or managed. Yet, just and appropriate interventions exist. The fundamental requirement is the empowerment of women, removing the barriers in many settings to their education (including environmental education, and the reproductive ethics of smaller families) and to realistic, voluntary access to contraception. Wherever “reproductive health” includes access to rights-based family planning, this not only promotes the health of the planet but also women’s health through, inter alia, their choice to have fewer and better-spaced children. This is ethical, pragmatic, and cost-effective—a prime example of preventive medicine. Politicians (mostly men) everywhere must embrace this long-term thinking and significantly increase the currently inadequate funding of contraceptive care. Herein is another Scientists’ Warning: there is just one planet for all life.

In its infinite wisdom, Nature has made human reproduction so pleasant that humans reproduce themselves very effectively. Reproduction is further cherished and reinforced by culture, religion, and economic forces. This massive pro-natalism engenders fertility levels which, if not balanced by high mortality, lead to relentless population growth.

Starting in the 19th century, human achievements in medicine and sanitation dramatically reduced worldwide death rates, especially in infancy. Birth rates, while not increasing, remained high, leading to an unprecedented human explosion from a base of circa 1.25 billion in 1850 to 8 billion in 2022. Further, assuming no massive increase in deaths from possible wars and pandemics, the median United Nations projection implies that growth will continue, with the human population possibly peaking at 10.4 billion in 2086.

According to the scientific literature, however, 2 to 3 billion is the maximum sustainable long-term human population, given the inevitable environmental impact.

In 2020, Sir Sabaratnam Arulkumaran, Emeritus Professor of Obstetrics and Gynaecology, St. George’s University of London, gave a keynote lecture at the All India Congress of Obstetrics and Gynaecology entitled The World Will Sink Without Contraception. The title says it all, and we agree with its content and clarity.

There is a way to ameliorate a situation where a large family is not a synonym for wealth but poverty, where too many children place a burden on the planet, the state, the school system, and more. “Demography is destiny” is erroneous, yet most authorities active in both development and the environment continue to see population growth as inevitable, a “given”, not amenable to intervention. We have an intervention, the technology known as contraception and the portfolio of measures that come under the umbrella of voluntary family planning programs. Yet, such authorities discount that, and so advocate publicly only to predict and provide for ever proliferating human numbers; despite that goal having become an impossible task on a finite planet, as most of these authorities privately admit. They often fear, neglecting the abundant evidence to the contrary, that we can do little about our growing numbers without coercive, deplorable measures such as forced sterilisations. This is to count on fate to solve our problems.

How will history judge us if we fail to grasp the dangers deriving from vast human numbers, and if we fail to protect this planet by dismissing the most humane and ethical thing to do, i.e., to provide all those who need and want birth control in every region with modern contraception and family planning, including legal abortion?

We must see that limiting our reproduction is the most ethical thing to do and think and act long-term, because there is just one planet for all of us. This is especially true for unintended births, but our family size intentions should also be reviewed in the light of intensifying environmental crises. After all, “we have not inherited the Earth from our grandparents, we have borrowed it from our grandchildren”.

It is self-evident that tomorrow’s world will, for our grandchildren and indeed for the whole Web of Life, be a happier and safer place if there are not overwhelmingly too many humans competing, often violently, for what remains from their ”loan” to us.

Sir David Attenborough on overpopulation

The Scientist’s Warning

Hastening the Inevitable Demographic Revolution | Christopher Tucker | TEDxPenn

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