Birthgap Facts

The Birthgap Project began in January 2016, when data scientist Stephen J. Shaw became increasingly concerned by the absence of an explanation for the expanding low-birthrate phenomenon across academia. Birthrates had been declining across many developed countries since the 1970s, yet no consistent global pattern had been identified to explain why societies with very different cultures, economies, and policies appeared to be following a near-identical trajectory.

Despite decades of research and vast amounts of demographic data, no common explanation had convincingly accounted for the persistent trend toward low birthrates. Shaw came to the view that data alone would not be sufficient and that, before undertaking any formal analysis, he needed to speak directly with people in the countries experiencing these shifts.

He began travelling internationally, meeting individuals and families in their homes, workplaces, and local communities. These conversations were not originally intended for a film. However, encouraged by his son, Shaw started recording the interviews. As the scale and depth of the personal accounts became clear, the decision was made to develop the project into a documentary.

Over the following nine years, Shaw met and interviewed more than 230 people across 24 countries. The project combined on-the-ground interviews, expert perspectives, and direct observation, gradually revealing recurring themes that were not apparent from statistics alone.

During the project’s second year, a common thread began to emerge across interviews conducted in very different social and cultural contexts. This observation later formed the basis of a formal analytical investigation. The resulting findings were 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.

Today, Birthgap·org operates as an independent research and public education platform focused on the structural drivers of declining birthrates. It brings together documentary storytelling, peer-reviewed research, live public dialogue, and accessible data resources within a single framework.

The project now extends beyond the original research program. It includes moderated global screening events through Birthgap Chats, ongoing policy engagement, collaboration with X·Y Worldwide – co-founded by Shaw as the world’s first nonprofit dedicated to awareness and policy guidance on the low birthrate phenomenon – and the development of data tools designed to make demographic trends more transparent and accessible to a broad audience.

At its core, Birthgap·org exists to bridge the gap between demographic research and everyday understanding – providing a clear lens through which well-intentioned explanations focused on income, unemployment, or work-life balance can be evaluated alongside the deeper structural patterns that more consistently shape family formation. The aim is to foster clearer public discourse and better-informed decisions about the future of population stability.

The project is grounded in empirical population data and peer-reviewed research. Its focus is on understanding structural patterns in fertility and parenthood timing as they appear in national birth records 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.

Beyond media coverage, research arising from the Birthgap Project has entered wider policy discussion across multiple regions. Its findings have been referenced by policymakers in several countries, including within the Organization for Security and Co-operation in Europe (OSCE), a 57-nation transatlantic body.

In July 2025, the OSCE adopted the Porto Declaration “Winter of Discontent”, addressing demographic challenges consistent with themes explored in the project. The work has also been presented in policy forums and academic settings, including invitations to contribute to discussions convened by the United Nations Population Division.

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 striking 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.

When this finding has been shared publicly, the most common reactions include surprise, disbelief, and often anger that this information was not more widely known. Many people assume they have far more time than the statistics suggest.

Birthgap·org prioritizes awareness because timing matters. Clear information about age-based fertility outcomes allows individuals to plan their education, careers, relationships, and family lives with a fuller understanding of the realities involved.

You can participate in a live Birthgap Chats event, host a local screening using our self-moderation guidance, or explore the research and data resources available through Birthgap·org.

The project exists to encourage informed, open conversation about demographic change. However you choose to engage, your participation helps broaden understanding of an issue shaping societies across the world.

Concerns about global population size and environmental sustainability vary, and are sometimes presented as reasons not to focus on declining birthrates. Yet 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.

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.

Not necessarily. Fertility decline reflects two distinct processes: whether people become parents at all, and how many children parents go on to have.

In many low-fertility countries, average family size among mothers has changed little for decades, in some cases since the 1970s. In the United States, average family size among mothers has modestly increased since the 1980s.

This means that much of the decline in total birthrates is not driven by parents having dramatically fewer children, but 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.

In the past, when most people who wanted to become parents did so – often at younger ages than today – a larger share of childlessness may reasonably have reflected voluntary choice. However, as parenthood has increasingly been delayed, substantial evidence from population data and academic literature indicates that both involuntary childlessness (resulting from medical or biological infertility, including unsuccessful fertility treatments) and unplanned childlessness (arising from circumstances such as not meeting a partner at the “right time”) have risen.

Given that stated desire for children has not declined notably – for example, as shown in the National Survey of Family Growth (NSFG) over several decades – and that medically defined infertility remains relatively uncommon at the population level, the inference is that unplanned childlessness now represents a larger share of overall childlessness.

Indeed, survey and longitudinal research consistently show a gap between fertility intentions earlier in life and outcomes later on. Peer-reviewed analysis from the Birthgap Project found that in core study countries – including Italy, Japan, the United Kingdom, and the United States – mothers generally achieved their stated desired family size.

This infers the fertility gap in these countries is not primarily the result of parents having fewer children than intended. Instead, it reflects a growing share of adults who never enter parenthood at all, despite earlier intentions to do so.

Furthermore, the increases in childlessness were observed as sudden, synchronized shifts across rural and metropolitan areas and across multiple nations – patterns inconsistent with a gradual biological change or a widespread, long-term shift in stated desire for children. The evidence therefore points toward structural and timing-related constraints as the dominant explanation for rising lifetime unplanned childlessness.

There is a large knowledge gap in our societies relating to the “Fertility Window,” based on real-world outcomes. In almost all low-fertility nations, population data show a consistent pattern: women who reach around age 30 without having had a first child have less than a 50% likelihood of ever having a child in the future. In many nations it is even younger – for example, age 26 in Japan and 28 in parts of Europe, including the UK. This information is important for young people planning their futures, yet many are led to assume that this threshold is reached much later in a woman’s 30s.

A further knowledge gap relates to medical advances such as IVF and egg freezing, which have expanded options for some individuals. However, at the population level, later-age first births remain relatively uncommon compared to the number of women who express intentions to have children. In fact, there is no meaningful uptick in national birth records that can be attributed to these advances, meaning that while some succeed, many others experience unsuccessful treatment or never get the chance to pursue it. Delaying parenthood therefore carries risks that are not always widely understood.

In most societies today, individuals who do not want children can choose not to become parents. However, for those who do want to become parents, outcomes are shaped by factors including finding a partner, settling down, and biology. Age increasingly becomes a constraint the longer parenthood is delayed – a pattern consistently visible in national birth records across many countries. Recognizing that outcomes are shaped by more than choice is central to 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.

Advances in technology and artificial intelligence can increase productivity and reduce the need for human labor in certain sectors. Automation may help societies manage workforce shortages or support aging populations in the short and medium term.

However, AI does not change how population dynamics work. If fewer children are born, there will be fewer adults in the future. Automation can replace certain tasks, but it does not create new generations of people.

Modern economies, tax systems, and social security structures are built around people – workers, consumers, and taxpayers. While technology can raise output, it does not itself contribute to demographic replacement or fiscal sustainability in the way growing working-age populations do.

Immigration may help individual countries slow workforce decline or temporarily increase the share of working-age adults. At a broader level, however, immigration redistributes people rather than creating new ones. It does not increase the total number of people being born globally.

Global annual births are already declining. Even countries long viewed as major sources of migration are now experiencing fertility decline – including India, where many states have had below-replacement fertility for years. As low birthrates become more widespread, the pool of younger populations available to migrate inevitably shrinks, making perpetual large-scale inflows difficult to sustain.

In addition, immigrants themselves grow older over time and eventually require support, just like the native-born population. For immigration alone to offset persistently low birthrates, sustained inflows at high levels would need to continue indefinitely.

Emigration also affects the communities people leave behind. In some areas, large numbers of younger adults move away, leaving older generations with fewer working-age people to support local economies and services. Immigration can influence national population outcomes, but it does not alter the broader global trend 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 population. But it does not automatically make housing cheaper, especially in economically dynamic cities where people continue to concentrate.

No. Sustained low fertility 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 are not limited to GDP figures or corporate profits. They influence how public services are financed and how societies distribute responsibility between generations. When fewer workers support more dependents, the strain is felt across households and public budgets.

And this is not simply about the number of older people alive today. If birthrates continue to shrink, each generation becomes smaller than the one before it. In that sense, the “boomer” imbalance does not disappear – it repeats. In a persistently low-fertility world, every generation eventually carries the demographic weight that boomers are often said to carry now.

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 combines large-scale demographic analysis with international field research and led to a feature length documentary. A novel finding of the project is that in many low-fertility countries, average family size among parents has remained relatively stable for decades, while delayed parenthood is strongly linked to rising lifetime childlessness. In practical terms, falling birthrates are driven mainly by fewer people becoming parents at all, rather than by parents choosing dramatically smaller families.

The term “Birthgap” was coined during the research behind the film to describe a straightforward idea: 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, this gap is expressed using generational comparisons:

• The Birthgap Generational Index (BGI) compares current births to the size of the generation of women of childbearing age.
• The Birthgap Retirement Index (BRI) compares current births to the size of the generation approaching retirement.

A BGI 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 rather than purely biological, 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 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, rather than to advocate specific personal or policy outcomes.

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 clarify the evidence so that those decisions can be made with a fuller understanding of demographic realities.

No. Birthgap.org is an independent, non-partisan platform. It is not affiliated with any political party, religious institution, or advocacy organizations, or other organizations of any kind.

The project is grounded in empirical research and open public dialogue. Its purpose is to clarify demographic patterns and support informed discussion, rather than to advance ideological or campaign objectives.

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

Today, Birthgap.org operates as an independent platform supported through voluntary donations, ticketed screening events, live Birthgap Chats, and optional subscriptions for extended content and discussions. Support in any of these forms helps sustain ongoing research, public dialogue, and open access to evidence-based materials.

The project does not receive funding from political parties, religious institutions, advocacy organizations, commercial sponsors, or any other external entity, and it does not promote outside agendas.

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.

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, and more broadly 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.

You can watch the documentary on demand, participate in a live Birthgap Chats event, explore research summaries and data resources, or follow ongoing podcasts and public discussions through Birthgap.org.

The project is designed to encourage informed engagement at multiple levels – whether through viewing, discussion, research, or community dialogue.

Birthgap Chats are scheduled, shared screening events rather than on-demand viewings. Each event presents segments of the film at a set time, followed by a live Q&A with Stephen J. Shaw.

The format is designed to encourage collective viewing and structured discussion. Participants can submit questions, hear additional context behind the research, and engage in dialogue – creating a moderated, reflective experience rather than a solitary stream.

Yes. Private Birthgap Chats events can be arranged following a brief screening process to ensure the event format reflects Birthgap’s non-partisan and evidence-based approach.

Please contact events@birthgap.org for further details.

Birthgap Briefings is a planned weekly podcast hosted by Stephen J. Shaw focused on demographic trends, new research, and current events related to falling birthrates and family formation.

The podcast is scheduled for launch in 2026 and will be available through Birthgap.org and major podcast platforms. It is intended to extend the project’s evidence-based approach into ongoing public analysis and discussion.

Public discussion of demographic change can generate differing interpretations and criticism. Birthgap’s core findings are based on large-scale national birth records and peer-reviewed academic research.

Readers are encouraged to consult the original published paper, review the referenced data sources, and assess the evidence directly. The project is committed to transparency in methods and documentation.