Birthgap Facts

The Birthgap Project began in January 2016, when data scientist Stephen J. Shaw grew concerned by the lack of a convincing explanation for the global decline in birthrates. Although fertility had been falling across many developed countries since the 1970s, no consistent pattern had been identified to explain why societies with very different cultures, economies, and policies were following nearly identical trajectories.

Despite decades of research and abundant demographic data, no common cause had adequately accounted for the persistent downward trend. Shaw concluded that data alone was not enough. He needed to speak directly with people living through these changes.

He began travelling internationally, meeting individuals and families in their homes, workplaces, and communities. What started as private conversations were not originally intended for a film. Encouraged by his son, Shaw began recording the interviews. As common themes emerged from the depth and scale of the personal stories, the project evolved into a documentary.

Over the following nine years, Shaw conducted more than 230 interviews across 24 countries. Combining on-the-ground conversations, expert insights, and direct observation, the project uncovered recurring patterns that statistics alone could not reveal.

The resulting research was developed into an academic paper, peer-reviewed, and published in a Nature Portfolio journal in 2025.

• 2016 – While studying at Harvard Extension School, Stephen J. Shaw begins investigating why birthrates were declining across multiple countries at the same time. He coins the term “Birthgap”, and the project formally begins.
• 2016–2020 – Research and filming proceed in parallel across 24 countries, with more than 230 interviews conducted. What began as a short project expands into a multi-year international investigation.
• 2017 – The Microdemographic Framework (MDF) is developed, distinguishing between how many people become parents and how many children parents have.
• 2020–2021 – Early versions of the documentary are selected for the New York Chelsea Film Festival.
• 2022 – Birthgap – Part 1 is released publicly on YouTube, attracting more than 500,000 views and generating significant international discussion.
• 2022–2024 – The project receives international media coverage, including appearances on major long-form podcasts and on BBC HARDtalk, as public debate around demographic change expands.
• 2025 – The completed feature-length documentary Birthgap is released. Research arising from the project is peer reviewed and published in a Nature Portfolio journal.
• 2026 – Two further research papers are submitted for peer review and the book charting the research journey and its findings is finally written, with a release planned for late 2026.

Today, Birthgap·org operates as a public education platform dedicated to the causes and consequences of declining birthrates. It brings together peer-reviewed research, documentary storytelling, live public dialogue, and accessible data resources.

At its core, Birthgap·org seeks to bridge the gap between granular research and everyday understanding, dispelling common myths and fostering clearer public discourse and better-informed decisions about the future of population stability.

No. The project is grounded in empirical population data and peer-reviewed research. Its focus is on understanding structural patterns in fertility and parenthood timing, consistent patterns across countries and decades.

Birthgap·org does not advocate for specific political parties, religious positions, or social ideologies. It does not take positions on issues such as abortion, gender roles, or family policy prescriptions. Its primary objective is awareness: ensuring that individuals and policymakers alike understand the demographic patterns that are already visible in the data.

By separating evidence from ideology, Birthgap·org seeks to contribute to informed discussion rather than partisan debate.

Research arising from the Birthgap Project has entered wider policy discussion across multiple regions. Its findings have been referenced by policymakers in several countries.

Key examples of engagement include:

• Organization for Security and Co-operation in Europe (OSCE) Parliamentary Assembly (2025): The official report of the Special Representative on Demographic Change and Security (full report) explicitly references Stephen J. Shaw’s research on childlessness patterns. Shaw keynoted related sessions, contributing to the first-ever transnational resolution on the birthrate crisis (Porto Declaration “Winter of Discontent”), adopted unanimously by representatives of 57 nations.
• European People’s Party (EPP): Referenced in the EPP paper “Responding to the Demographic Winter” (full paper). The EPP is the largest political grouping in the European Union.
• Centre for Social Justice (CSJ) in the UK: The CSJ’s report “Baby Bust” (full report) draws on the research, including analysis of fertility trends and the Microdemographic Framework.

As demographic pressures intensify in many societies, the research continues to inform dialogue among policymakers and institutions on multiple continents. Consultation and advisory discussions have focused particularly on the structural drivers of delayed parenthood, rising childlessness, and long-term population sustainability.

There is a significant gap between young people’s expectations about the timing of parenthood and what the data actually show. These patterns are rarely discussed openly or communicated clearly.

Birth timing data from millions of mothers across many countries reveal a consistent pattern: by around age 30, a woman who has not yet had a first child faces roughly a 50/50 chance of ever becoming a mother. In several countries this tipping point occurs even earlier.

This outcome is only loosely related to biology. Other barriers — particularly finding a partner who is ready to have children at the same time — often have a more dramatic impact and emerge at a younger age than biological constraints.

When this finding is shared publicly, the most common reactions are surprise, disbelief, and sometimes anger that the information was not more widely known. Many people assume they have far more time than birth records reveal.

Birthgap·org prioritizes awareness because timing matters. Clear, evidence-based information about age-related fertility outcomes enables individuals to make more informed decisions about education, careers, relationships, and family planning.

You can participate directly through local awareness initiatives and discussions via the non-profit X·Y Worldwide, founded by Stephen J. Shaw and Katalin Novák, former President of Hungary. X·Y Worldwide supports education programs and local awareness efforts in schools, colleges, community groups, and workplaces. More information coming soon.

Donations to Birthgap.org are also particularly welcome. We receive no funding from any political, religious, or ideological organizations. The Birthgap project exists to encourage informed, open conversation about demographic change. Your support helps broaden understanding of an issue that is shaping societies across the world.

The core findings are based on official national birth registration data covering entire populations, drawn from publicly accessible statistical agencies and international databases such as the Human Fertility Database.

These administrative records represent over 300 million mothers across more than 40 countries, often spanning from the 1970s to the present day. The analysis uses comprehensive national datasets rather than surveys or limited samples.

All sources, definitions, and methodological steps are clearly documented in the peer-reviewed paper, allowing full transparency and independent replication.

Research arising from the Birthgap Project, authored by Stephen J. Shaw, was peer-reviewed and published in a Nature Portfolio journal in 2025. The study analyzes large national birth datasets from high-income countries. Read the full paper here.

Drawing on records for over 300 million mothers across more than 40 countries — many of which extend back to the 1970s or earlier — the analysis is based on comprehensive national administrative birth records rather than survey-based samples or limited cohort studies.

Stephen J. Shaw is a published, independent researcher and data scientist with more than two decades of experience in data science. His work on fertility dynamics and age-structured outcomes has been peer-reviewed and published in a Nature Portfolio journal in 2025.

In addition to academic publication, findings from the Birthgap Project have been presented and discussed in senior policy settings, including ministerial-level engagements, European Union institutions, and by invitation at the United Nations Population Division.

Further academic work building on these findings is currently underway.

Concerns about global population size and environmental sustainability vary, and are sometimes presented as reasons not to focus on declining birthrates. Yet this is in many ways yesterday’s question. Global annual births peaked around 2013 and have been falling since. Worldwide fertility has declined for decades and is now below the level needed to maintain long-term population stability (around 2.1 children per woman). If sustained, this places the global population on a delayed but structurally downward path.

So why is the world’s population still growing? The answer lies in mortality, not rising births. Even though total births are declining, many countries have seen large increases in life expectancy over recent decades. When people who once might have died at 40 now live into their 70s, the number of people alive at any given time rises substantially. As long as annual births still exceed annual deaths, population continues to grow.

But longevity gains cannot expand indefinitely. As improvements in survival slow and large generations age, annual deaths eventually rise. If fertility remains below replacement, that balance shifts — and population growth slows, before ultimately reversing.

Regardless of one’s broader view on population size, understanding why fertility has fallen so widely — and so quickly — remains an essential demographic question. A demographic shift of this scale warrants serious attention.

A better question may be whether families — small or large — can live sustainably. On this point, there is little reason to say they cannot.

No. Low and falling fertility is no longer limited to wealthy or Western societies. Over the past two decades, birthrates have declined across Latin America, South and East Asia, the Middle East, and increasingly parts of Sub-Saharan Africa.

Today, countries where fertility is below the level needed to maintain long-term population stability account for roughly three-quarters of the world’s population – including nations such as India and China. The pattern is not confined to a particular culture, religion, or income level.

While the speed and timing of decline differ between regions, the overall direction is global. The question is no longer whether fertility decline is spreading – but how far and how fast it will continue.

No. Research has shown that most people in higher-resource nations still intend to have 2 or 3 children — a preference that has remained remarkably stable for decades. In fact, in many low-fertility countries, the average family size among mothers who do have children has changed little since the 1970s. In the United States, it has even modestly increased since the 1980s.

Much of the recent decline in total birthrates is unrelated to family size, but driven by a rising share of adults who never enter parenthood at all — often linked to delayed timing. That distinction is central to understanding the low-birthrate phenomenon.

First, how can we tell whether the rise in childlessness is mostly planned or unplanned? Robust surveys show that women’s stated desire for children has remained consistently high for decades. For example, the U.S. National Survey of Family Growth (NSFG) — based on in-person interviews with over 5,000 women and men — finds that ~90% or more of women have or want children by their early 30s. Yet with childlessness now trending toward 40% or more among women in developed nations, unplanned childlessness — driven primarily by personal circumstances — now accounts for the dominant share of overall childlessness.

This is supported by a consistent gap between earlier fertility intentions and later outcomes. Peer-reviewed analysis across OECD countries (including Italy, Japan, the United Kingdom, and the United States) shows that mothers generally achieve their desired family size. Given that women who do have children largely reach their intended family size, the overall fertility gap is concentrated among those who wanted children but remained childless.

But this goes beyond higher-resource nations. According to the 2026 United Nations Population Division global report Lives, Choices and Futures, 72% of women and 80% of men aged 35–39 without children still ideally want them.

Multiple lines of evidence therefore point to the fertility gap being largely driven by unplanned childlessness (primarily circumstantial, such as not finding a suitable partner at the right time). Increased involuntary childlessness (due to medical or biological infertility) has also played a role. As parenthood has been increasingly delayed, both have risen significantly.

There is a large knowledge gap around the real-world “fertility window.” In almost all low-fertility nations, data show that women who reach age 30 without a first child have less than a 50% chance of ever having one. In many countries this tipping point is even earlier (e.g., age 26 in the US, Canada, and Japan; age 28–29 in the UK and much of Europe). Yet many young people assume they have far more time.

Medical advances like IVF and egg freezing have helped some individuals, but at the population level they have not produced a meaningful increase in births. Later-age first births remain relatively uncommon, and many who delay never get the chance to become parents.

For those who want children, outcomes are shaped by more than choice — including finding a partner, settling down, and biology. Age becomes an increasing constraint the longer parenthood is delayed. Recognizing these realities is central to truly informed decision-making.

Neither. The data do not support framing fertility decline as the fault of either men or women.

Across low-fertility societies, delayed parenthood reduces the likelihood of becoming a parent for everyone. The patterns visible in national birth records are structural and societal, rather than specific to either men or women.

It may feel natural to assign responsibility to one group or the other, but declining birthrates reflect broader timing and partnership dynamics that affect both sexes alike.

At the same time, better data on men is needed. Birth registration systems have traditionally captured detailed information about mothers at childbirth, while data on fathers is often more limited or inconsistently recorded. A fuller understanding of fertility dynamics requires improved data collection on fatherhood as well.

No, AI and technology cannot directly influence this trend. If fewer children are born today, there will be fewer adults in the future. Fewer adults mean even fewer children, and so on. This is exponential decline — a simple mathematical reality that continues as long as birthrates remain below replacement level, with or without robots.

No amount of artificial intelligence changes this fundamental dynamic. Technology may help manage the symptoms of population aging, but it cannot stop the long-term contraction of human populations.

Birthgap·org believes every nation has the sovereign right to determine the level of immigration that is best for it — whether high or low. However, in the context of birthrate decline, immigration can only provide a limited, shorter-term impact. Conflating the two issues is rarely helpful for clear discussion.

Immigration may temporarily slow workforce decline or increase the share of working-age adults. However, immigrants themselves age over time and eventually require support, just like the native-born population. For immigration alone to fully offset persistently low birthrates, extremely high levels of inflows would need to continue indefinitely.

At a broader level, immigration redistributes people. It does not increase the total number of births globally, and global annual births are already declining. Even traditional source countries of migration — including many states in India — are now experiencing low fertility on European and American levels. As low birthrates spread worldwide, the pool of potential migrants will inevitably shrink.

Emigration can also strain the communities people leave behind, leaving fewer working-age adults to support local economies and older generations. While immigration can influence national population trends, it does not alter the broader global reality of falling fertility.

Not necessarily. Housing markets are shaped by location, employment patterns, land supply, and financial conditions – not population size alone.

Japan provides a useful example. Although its national population has been declining for years, housing demand remains strong in Tokyo and other major urban centers. At the same time, many rural areas face falling prices and rising vacancy rates. However, these areas often experience declining services – such as school closures and reduced public transport – as populations shrink, which can make them less attractive places to live.

Birthrate decline may influence housing markets over time, particularly in areas already losing working-age population. But it does not automatically make housing cheaper universally, especially in economically dynamic cities where people continue to concentrate.

Absolutely not. Sustained low fertility fundamentally reshapes the balance between working-age adults and those who depend on them — including children, retirees, and people requiring care. Over time, this affects pensions, healthcare systems, education funding, and the availability of social support.

These pressures go far beyond GDP figures or corporate profits. They directly influence how public services are financed and how responsibility is shared between generations. When fewer workers support more dependents, the strain is felt across households, communities, and public budgets alike.

A website called birthgapfacts.org (which is not affiliated with Birthgap.org) publishes a critique of the Birthgap documentary and related research. Much of the content was written before the full-length documentary was released and before the principal findings of the Birthgap Project had undergone peer review.

The site includes statements attributed to the documentary or to Stephen J. Shaw that did not appear in the film or do not accurately reflect the original wording or context. Other criticisms focus on interpretations of interview material or public messaging rather than on the statistical methods or empirical findings in the published research.

For a point-by-point verification of specific claims against primary sources, see the complete Evidence Index:
→ https://evidence.birthgap.org

As with any scientific topic, primary evidence, transparent methodology, and peer-reviewed research provide the strongest basis for evaluating competing claims.

→ Read the 2025 peer-reviewed paper

Yes. Birthgap·org is grounded in independent, peer-reviewed research by data scientist and demographer Stephen J. Shaw, published in a Nature Portfolio journal in 2025. The study draws on large national administrative birth datasets covering hundreds of millions of recorded births across multiple countries and decades, rather than relying primarily on sample surveys or limited cohort studies.

The Birthgap Project began in 2016 as an independent research initiative led by Stephen J. Shaw to examine why birthrates have been falling across many modern societies. It led to the peer-reviewed identification of unplanned childlessness as a common pattern across most low-fertility nations. A key finding is that in many of these countries, average family size among parents who do have children has remained relatively stable for decades. The main driver of falling birthrates is therefore fewer people becoming parents at all, often linked to delayed timing, rather than parents choosing dramatically smaller families.

The term “Birthgap” was coined during the research behind the film to describe the growing gap between the number of children being born today and the number needed to maintain long-term population stability.

In the film and related research, the birthgap is expressed using generational comparisons:

• The Total Fertility Gap (TFG) compares current births to the size of the generation of women of childbearing age.
• The Future Workforce Gap (FWG) compares current births to the size of the generation aged 50 who will retire in around 20 years.

A TFG of 33%, for example, indicates that births are roughly one-third below the level required for replacement over time. This corresponds to a commonly cited Total Fertility Rate (TFR) of about 1.4, compared with a replacement level of approximately 2.1 children per woman.

The term Birthgap is intended to make this demographic shortfall easier to visualize and discuss — as a measurable generational imbalance with long-term social and economic implications.

In the research underlying Birthgap, unplanned childlessness refers to individuals who intended or expected to have children but did not ultimately become parents. The reasons are often structural, and may include delayed timing, partnership dynamics, or broader life circumstances.

This differs from voluntary childlessness, which reflects a clear decision not to have children, and from involuntary childlessness, which refers specifically to medical or biological infertility.

Birthgap.org is the public awareness platform that grew out of the original Birthgap Project, led by Stephen J. Shaw. Following the identification of a structural link between delayed parenthood and rising unplanned childlessness – referring to individuals who intended to have children but ultimately did not – the project expanded into a broader public education initiative.

Today, Birthgap.org communicates its findings through documentary film, live events, podcasts, and accessible research summaries. Its purpose is to support informed, evidence-based discussion about demographic change.

No. Birthgap·org does not prescribe personal decisions or promote population targets. Its focus is on examining observable demographic patterns – understanding what is happening, why it is happening, and why similar trends appear across many societies.

The project supports the principle that individuals are free to choose whether to have children or remain childless. Its role is to identify and share the data-driven evidence so that those decisions can be made with a fuller understanding of demographic realities.

Birthgap·org is an independent, non-partisan platform. It is not affiliated with any political party, religious institution, advocacy organization, or any other entity.

It collaborates with X·Y Worldwide, a non-profit organization founded by Stephen J. Shaw and Katalin Novák to deliver education and awareness programs in communities around the world, along with data-driven policy advice.

X·Y Worldwide is a non-profit organization co-founded by Katalin Novák, former President of Hungary, and Stephen J. Shaw. It focuses on policy research, community volunteer programs, and public awareness related to unplanned childlessness and demographic change.

Birthgap.org centers on academic research and public discussion. X·Y Worldwide focuses on local engagement and volunteer initiatives, as well as policy research. The two organizations are separate but work toward related goals.

The original Birthgap Project — including its research, international fieldwork, and documentary production — was self-funded by Stephen J. Shaw.

Today, Birthgap.org is supported through voluntary donations. These contributions help sustain ongoing research, public dialogue, and open access to evidence-based materials, including the Birthgap Barometer on this website.

The project does not seek or receive funding from governments, political parties, religious institutions, advocacy organizations, commercial sponsors, or any other external entities.

Birthgap·org is for anyone seeking a clearer understanding of how falling birthrates are reshaping modern societies. This includes younger adults making life decisions, parents and non-parents concerned about the societies they live in, educators, community leaders, policymakers, researchers, and members of the general public.

The project is designed to make complex demographic patterns accessible without oversimplifying them, supporting informed discussion across generations and perspectives.