In the United States, the crude birth rate in 1800 was 48.3 live births per thousand people, meaning that 4.8 percent of the population had been born in that year. Between 1815 and 1825 the crude birth rate jumped from 46.5 to 54.7 (possibly due to Florida becoming a part of the US, but this is unclear), but from this point until the Second World War the crude birth rate dropped gradually, reaching 19.2 in 1935. Through the 1940s, 50s and 60s the US experienced it's baby boom, and the birth rate reached 24.1 in 1955, before dropping again until 1980. From the 1980s until today the birth rate's decline has slowed, and is expected to reach twelve in 2020, meaning that just over 1 percent of the population will be born in 2020.

The fertility rate of a country is the average number of children that women from that country will have throughout their reproductive years. In the United States in 1800, the average woman of childbearing age would have seven children over the course of their lifetime. As factors such as technology, hygiene, medicine and education improved, women were having fewer children than before, reaching just two children per woman in 1940. This changed quite dramatically in the aftermath of the Second World War, rising sharply to over 3.5 children per woman in 1960 (children born between 1946 and 1964 are nowadays known as the 'Baby Boomer' generation, and they make up roughly twenty percent of todays US population). Due to the end of the baby boom and increased access to contraception, fertility reached it's lowest point in the US in 1980, where it was just 1.77. It did however rise to over two children per woman between 1995 and 2010, although it is expected to drop again by 2020, to just 1.78.

While the standard image of the nuclear family with two parents and 2.5 children has persisted in the American imagination, the number of births in the U.S. has steadily been decreasing since 1990, with about 3.6 million babies born in 2023. In 1990, this figure was 4.16 million. Birth and replacement rates A country’s birth rate is defined as the number of live births per 1,000 inhabitants, and it is this particularly important number that has been decreasing over the past few decades. The declining birth rate is not solely an American problem, with EU member states showing comparable rates to the U.S. Additionally, each country has what is called a “replacement rate.” The replacement rate is the rate of fertility needed to keep a population stable when compared with the death rate. In the U.S., the fertility rate needed to keep the population stable is around 2.1 children per woman, but this figure was at 1.67 in 2022. Falling birth rates Currently, there is much discussion as to what exactly is causing the birth rate to decrease in the United States. There seem to be several factors in play, including longer life expectancies, financial concerns (such as the economic crisis of 2008), and an increased focus on careers, all of which are causing people to wait longer to start a family. How international governments will handle falling populations remains to be seen, but what is clear is that the declining birth rate is a multifaceted problem without an easy solution.

This collection contains five modified data sets with mortality, population, and other demographic information for five American cities (Baltimore, Maryland; Boston, Massachusetts; New Orleans, Louisiana; New York City (Manhattan only), New York; and Philadelphia, Pennsylvania) from the early 19th century to the early 20th century. Mortality was represented by an annual crude death rate (deaths per 1000 population per year). The population was linearly interpolated from U.S. Census data and state census data (for Boston and New York City). All data sets include variables for year, total deaths, census populations, estimated annual linearly interpolated populations, and crude death rate. The Baltimore data set (DS0001) also provides birth and death rate variables based on race and slave status demographics, as well as a variable for stillbirths. The Philadelphia data set (DS0005) also includes variables for total births, total infant deaths, crude birth rate, and infant deaths per 1,000 live births.

The fertility rate of a country is the average number of children that women from that country would have throughout their reproductive years. In the United Kingdom in 1800, the average woman of childbearing age would have five children over the course of their lifetime. Over the next 35 years the fertility rate was quite sporadic, rising to over 5.5 in the 1810s and 1820s, then dropping to 4.9 by 1835. This was during and after the Napoleonic Wars and the War of 1812 with the US, which was a time of increased industrialization, economic depression and high unemployment after the war. As things became more stable, and the 'Pax Britannica' (a period of relative, international peace and economic prosperity for the British Empire) came into full effect, the fertility rate plateaued until 1880, before dropping gradually until the First World War. The fertility rate then jumped from 2.6 to 3.1 children per woman between 1915 and 1920, as many men returned from the war. It then resumed it's previous trajectory in the interwar years, before increasing yet again after the war (albeit, for a much longer time than after WWI), in what is known as the 'Baby Boom'. Like the US, the Baby Boom lasted until around 1980, where it then fell to 1.7 children per woman, and it has remained around this number (between 1.66 and 1.87) since then.

The total fertility rate of the world has dropped from around 5 children per woman in 1950, to 2.2 children per woman in 2025, which means that women today are having fewer than half the number of children that women did 75 years ago. Replacement level fertility This change has come as a result of the global demographic transition, and is influenced by factors such as the significant reduction in infant and child mortality, reduced number of child marriages, increased educational and vocational opportunities for women, and the increased efficacy and availability of contraception. While this change has become synonymous with societal progress, it does have wide-reaching demographic impact - if the global average falls below replacement level (roughly 2.1 children per woman), as is expected to happen in the 2050s, then this will lead to long-term population decline on a global scale. Regional variations When broken down by continent, Africa is the only region with a fertility rate above the global average, and, alongside Oceania, it is the only region with a fertility rate above replacement level. Until the 1980s, the average woman in Africa could expect to have 6-7 children over the course of their lifetime, and there are still several countries in Africa where women can still expect to have 5 or more children in 2025. Historically, Europe has had the lowest fertility rates in the world over the past century, falling below replacement level in 1975. Europe's population has grown through a combination of migration and increasing life expectancy, however even high immigration rates could not prevent its population from going into decline in 2021.

The child mortality rate in the United States, for children under the age of five, was 462.9 deaths per thousand births in 1800. This means that for every thousand babies born in 1800, over 46 percent did not make it to their fifth birthday. Over the course of the next 220 years, this number has dropped drastically, and the rate has dropped to its lowest point ever in 2020 where it is just seven deaths per thousand births. Although the child mortality rate has decreased greatly over this 220 year period, there were two occasions where it increased; in the 1870s, as a result of the fourth cholera pandemic, smallpox outbreaks, and yellow fever, and in the late 1910s, due to the Spanish Flu pandemic.

The COVID-19 pandemic increased the global death rate, reaching *** in 2021, but had little to no significant impact on birth rates, causing population growth to dip slightly. On a global level, population growth is determined by the difference between the birth and death rates, known as the rate of natural change. On a national or regional level, migration also affects population change. Ongoing trends Since the middle of the 20th century, the global birth rate has been well above the global death rate; however, the gap between these figures has grown closer in recent years. The death rate is projected to overtake the birth rate in the 2080s, which means that the world's population will then go into decline. In the future, death rates will increase due to ageing populations across the world and a plateau in life expectancy. Why does this change? There are many reasons for the decline in death and birth rates in recent decades. Falling death rates have been driven by a reduction in infant and child mortality, as well as increased life expectancy. Falling birth rates were also driven by the reduction in child mortality, whereby mothers would have fewer children as survival rates rose - other factors include the drop in child marriage, improved contraception access and efficacy, and women choosing to have children later in life.

Over the past 70 years in the United States, women have gradually started having children at a later point in their lives. Before the *****, women in their early twenties had the highest birth rates, however women in their late twenties had the highest rates between 1980 and 2015, but were recently overtaken by women in their early thirties. Another major trend is the decline of teenage pregnancies, which was less than a quarter of it's ********* rate in the years between 2015 and 2020. In fact, birth rates among ***** years olds often doubled birth rates of women aged ***** throughout the late twentieth century, but in 2020, the opposite is true.

For women in their forties, birth rates have remained comparatively lower than rates among the other age groups. The high figures in the ***** and *****, can be attributed to the baby boom that followed the Second World War. In more recent decades, rising birth rates among older age groups is not only due to societal trends, but has also been aided by improvements in assisted reproductive technology (ART), such as in vitro fertilization (IVF). Such technologies have granted thousands of women the ability to conceive in circumstances where this would not have been possible in years past.

From the mid-19th century until today, life expectancy at birth in the United States has roughly doubled, from 39.4 years in 1850 to 79.6 years in 2025. It is estimated that life expectancy in the U.S. began its upward trajectory in the 1880s, largely driven by the decline in infant and child mortality through factors such as vaccination programs, antibiotics, and other healthcare advancements. Improved food security and access to clean water, as well as general increases in living standards (such as better housing, education, and increased safety) also contributed to a rise in life expectancy across all age brackets. There were notable dips in life expectancy; with an eight year drop during the American Civil War in the 1860s, a seven year drop during the Spanish Flu empidemic in 1918, and a 2.5 year drop during the Covid-19 pandemic. There were also notable plateaus (and minor decreases) not due to major historical events, such as that of the 2010s, which has been attributed to a combination of factors such as unhealthy lifestyles, poor access to healthcare, poverty, and increased suicide rates, among others. However, despite the rate of progress slowing since the 1950s, most decades do see a general increase in the long term, and current UN projections predict that life expectancy at birth in the U.S. will increase by another nine years before the end of the century.

For most of the past two centuries, falling birth rates have been associated with societal progress. During the demographic transition, where pre-industrial societies modernize in terms of fertility and mortality, falling death rates, especially among infants and children, are the first major change. In response, as more children survive into adulthood, women have fewer children as the need to compensate for child mortality declines. This transition has happened at different times across the world and is an ongoing process, with early industrial countries being the first to transition, and Sub-Saharan African countries being the most recent to do so. Additionally, some Asian countries (particularly China through government policy) have gone through their demographic transitions at a much faster pace than those deemed more developed. Today, in countries such as Japan, Italy, and Germany, birth rates have fallen well below death rates; this is no longer considered a positive demographic trend, as it leads to natural population decline, and may create an over-aged population that could place a burden on healthcare systems.

A global phenomenon, known as the demographic transition, has seen life expectancy from birth increase rapidly over the past two centuries. In pre-industrial societies, the average life expectancy was around 24 years, and it is believed that this was the case throughout most of history, and in all regions. The demographic transition then began in the industrial societies of Europe, North America, and the West Pacific around the turn of the 19th century, and life expectancy rose accordingly. Latin America was the next region to follow, before Africa and most Asian populations saw their life expectancy rise throughout the 20th century.

In 2024, the average life expectancy in the world was 71 years for men and 76 years for women. The lowest life expectancies were found in Africa, while Oceania and Europe had the highest. What is life expectancy?Life expectancy is defined as a statistical measure of how long a person may live, based on demographic factors such as gender, current age, and most importantly the year of their birth. The most commonly used measure of life expectancy is life expectancy at birth or at age zero. The calculation is based on the assumption that mortality rates at each age were to remain constant in the future. Life expectancy has changed drastically over time, especially during the past 200 years. In the early 20th century, the average life expectancy at birth in the developed world stood at 31 years. It has grown to an average of 70 and 75 years for males and females respectively, and is expected to keep on growing with advances in medical treatment and living standards continuing. Highest and lowest life expectancy worldwide Life expectancy still varies greatly between different regions and countries of the world. The biggest impact on life expectancy is the quality of public health, medical care, and diet. As of 2022, the countries with the highest life expectancy were Japan, Liechtenstein, Switzerland, and Australia, all at 84–83 years. Most of the countries with the lowest life expectancy are mostly African countries. The ranking was led by the Chad, Nigeria, and Lesotho with 53–54 years.

The world's population first reached one billion people in 1805, and reached eight billion in 2022, and will peak at almost 10.2 billion by the end of the century. Although it took thousands of years to reach one billion people, it did so at the beginning of a phenomenon known as the demographic transition; from this point onwards, population growth has skyrocketed, and since the 1960s the population has increased by one billion people every 12 to 15 years. The demographic transition sees a sharp drop in mortality due to factors such as vaccination, sanitation, and improved food supply; the population boom that follows is due to increased survival rates among children and higher life expectancy among the general population; and fertility then drops in response to this population growth. Regional differences The demographic transition is a global phenomenon, but it has taken place at different times across the world. The industrialized countries of Europe and North America were the first to go through this process, followed by some states in the Western Pacific. Latin America's population then began growing at the turn of the 20th century, but the most significant period of global population growth occurred as Asia progressed in the late-1900s. As of the early 21st century, almost two-thirds of the world's population lives in Asia, although this is set to change significantly in the coming decades. Future growth The growth of Africa's population, particularly in Sub-Saharan Africa, will have the largest impact on global demographics in this century. From 2000 to 2100, it is expected that Africa's population will have increased by a factor of almost five. It overtook Europe in size in the late 1990s, and overtook the Americas a few years later. In contrast to Africa, Europe's population is now in decline, as birth rates are consistently below death rates in many countries, especially in the south and east, resulting in natural population decline. Similarly, the population of the Americas and Asia are expected to go into decline in the second half of this century, and only Oceania's population will still be growing alongside Africa. By 2100, the world's population will have over three billion more than today, with the vast majority of this concentrated in Africa. Demographers predict that climate change is exacerbating many of the challenges that currently hinder progress in Africa, such as political and food instability; if Africa's transition is prolonged, then it may result in further population growth that would place a strain on the region's resources, however, curbing this growth earlier would alleviate some of the pressure created by climate change.

In 2023, around **** percent of all live births were delivered by cesarean section in the United States. The rate of c-section in the U.S. has been increasing since 1997 where it was **** percent to a peak of **** percent in 2009. C-section rate has since varied little and stayed around ** percent.

Among all countries that are part of the Organization for Economic Co-operation and Development (OECD), Turkey, followed by Korea, had the highest rate of Caesarean section births (or C-sections) in 2022. At that time, the rate of C-sections in Turkey was roughly 600 per 1,000 live births. Among global regions, Latin America and the Caribbean had the highest percentage of births that were delivered by C-section, while sub-Saharan Africa had the lowest rates of Cesarean section births. Cesarean section costs A Cesarean section is a form of birth where the baby is taken out through a surgical incision in the abdomen rather than a natural vaginal birth. The cost of a Cesarean section delivery varies globally, with the United States having the highest cost globally for Cesarean section deliveries, while Germany the lowest cost among selected countries worldwide. In the United States, C-sections are significantly more expensive than a delivery by vaginal birth. High C-sections rates in the U.S. Over the past 20 years the C-section rate in the U.S. has gradually been increasing with more stable trends in the past few years. It has been reported that many of the C-sections performed in the U.S. are elective and not necessary. Often, the risks of C-sections are greater than the benefits, when performed as an elective procedure. Therefore, the United States has a "healthy people target" for the c-section rate of first time, low-risk mothers. However, less than half of hospitals are meeting the national targets for Cesarean sections performed.

In 2022, there were around 613 thousand legal abortions in the United States. The number of legal abortions in the United States has decreased significantly since the early 1990’s. This number will probably continue to decrease in the coming years since many states have severely limited or completely banned abortion after the overturning of Roe v. Wade by the Supreme Court in 2022. The states with the highest abortion rates In 2022, the rate of legal abortions per live births in the United States was 19.9 per 100. In comparison, in 1990 there were 34.4 abortions per 100 live births. The states with the highest rates of abortion per live births are New Mexico, Illinois, and Florida. In Florida, there were around 37 abortions per 100 live births in 2022. Florida had the highest total number of abortions that year, followed by New York and Illinois. Missouri and South Dakota had the lowest number of abortions in 2022. Out-of-state abortions Critics of the Supreme Court decision to overturn Roe v. Wade argue that while those who can afford it may be able to travel to other states for an abortion if their state bans the procedure, poorer residents will have no such choice. Even before the overturning of Roe v. Wade, out-of-state residents already accounted for a high share of abortions in certain states. In 2022, 69 percent of abortions in Kansas were performed on out-of-state residents, while out-of-state residents accounted for around 62 percent of abortions in New Mexico. Illinois had the highest total number of abortions performed on out-of-state residents that year, with around 16,849 procedures.

Cesarean section rates increased with increasing age of mother in the United Sates. In 2023, around 18.9 percent of mothers under the age of 20 gave birth via c-section, while the rate of cesarean delivery for mothers aged 40 to 54 was 48.1 percent. In the recorded time period, c-section rates for most age groups peaked in 2007 and has decreased slightly since then.

The 45 men who have served as the President of the United States (officially there have been 46 as Grover Cleveland is counted twice) have fathered, adopted or allegedly fathered at least 190 children. Of these 190, 169 were conceived naturally, eleven were adopted and there are ten reasonable cases of alleged paternity (possibly more). Today, there are 34 living presidential children; the oldest of which is Lynda Bird Johnson Robb, daughter of Lyndon B. and Lady Bird Johnson; the youngest is Barron Trump, son of Donald and Melania Trump. John Tyler is the president who fathered the most children, having fifteen children over two marriages (and allegedly fathering more with slaves), while his successor, James K. Polk, remains the only U.S. president never to have fathered or adopted any known children. Coincidentally, as of November 2020, the U.S.' tenth president, John Tyler, has two grandsons who are still alive today, despite the fact that he was born in 1790.

The First Family

The president, their children and spouse are collectively known as the First Family of the United States; the current first family is made up of President Joe Biden, First Lady Jill Biden, as well as their children, Hunter and Ashley. Two of President Biden's children died before he was elected to office; his son Beau died of cancer in 2015, while his one year old daughter Naomi was killed in a car accident in 1972, along with Biden's wife, Neilia (who was also Beau and Hunter's mother). Two presidents' sons have gone on to assume the presidency themselves; these were John Quincy Adams and George W. Bush respectively, while one presidential grandson, Benjamin Harrison, later became president.

Alleged children

Three U.S. presidents have allegedly fathered illegitimate children with slaves. The most well-known and substantial of these allegations relates to Thomas Jefferson and his slave, Sally Hemings; who was also the half-sister of Jefferson's wife Martha (with whom he had already fathered six children). Following Martha's passing in 1782, its is believed that the future-president would then go on to have a relationship with Hemings that spanned four decades and saw the birth of as many as eight children between 1790 and 1808. Hemings, thought to have been 14 years old at the beginning of the relationship (Jefferson was 44), and her children remained enslaved to Jefferson until his death in 1826. DNA tests conducted in recent years have confirmed a genetic connection between the Hemings and Jefferson families, and the majority of historians accept that Thomas Jefferson was the father of at least six of Hemings' children. Less substantial claims have also been levelled at John Tyler, with political opponents claiming that he fathered several children with slaves in the years following his first wife's death; although these claims have been widely disregarded by historians, with little investigation into their validity. It is alleged that William Henry Harrison also fathered at least six children with one of his slaves, Dilsia, however these claims are anecdotal and have been disregarded or ignored by historians. In spite of this, to this day, there are some African-American families in the U.S. who claim to be the descendants of both Harrison and Tyler.

It is generally accepted that two other presidents, Grover Cleveland and Warren G. Harding, fathered children through extramarital affairs. It is likely that Grover Cleveland had fathered a child out of wedlock in 1874; even paying child support to the mother, acknowledging that he could have been the father. When the child's mother accused Cleveland of rape, he had her institutionalized to discredit these accusations, and the child was taken away and raised by Cleveland's friends. The issue came to light nationally during the 1884 election campaign, but Cleveland still emerged victorious. In 1927, four years after his death in office, it came to light that Warren G. Harding had fathered a child out of wedlock a year before winning the 1920 election. The child was conceived during one of his two long-term, extramarital affairs, and Harding did pay the mother child support, although he kept the affair and child a secret. Harding died before the child's fourth birthday, his family dismissed these claims as rumors, claiming that he was infertile; however, DNA tests confirmed that the child was his in 2015. While there have been numerous accusations of presidents' infidelity in the past century, particularly relating to John F. Kennedy and Donald Trump; Trump is the only president since Harding to have had a child out of wedlock (although the couple did get married two months after the birth of their daughter, Tiffany).

In 2025, India overtook China as the world's most populous country and now has almost 1.46 billion people. China now has the second-largest population in the world, still with just over 1.4 billion inhabitants, however, its population went into decline in 2023. Global population As of 2025, the world's population stands at almost 8.2 billion people and is expected to reach around 10.3 billion people in the 2080s, when it will then go into decline. Due to improved healthcare, sanitation, and general living conditions, the global population continues to increase; mortality rates (particularly among infants and children) are decreasing and the median age of the world population has steadily increased for decades. As for the average life expectancy in industrial and developing countries, the gap has narrowed significantly since the mid-20th century. Asia is the most populous continent on Earth; 11 of the 20 largest countries are located there. It leads the ranking of the global population by continent by far, reporting four times as many inhabitants as Africa. The Demographic Transition The population explosion over the past two centuries is part of a phenomenon known as the demographic transition. Simply put, this transition results from a drastic reduction in mortality, which then leads to a reduction in fertility, and increase in life expectancy; this interim period where death rates are low and birth rates are high is where this population explosion occurs, and population growth can remain high as the population ages. In today's most-developed countries, the transition generally began with industrialization in the 1800s, and growth has now stabilized as birth and mortality rates have re-balanced. Across less-developed countries, the stage of this transition varies; for example, China is at a later stage than India, which accounts for the change in which country is more populous - understanding the demographic transition can help understand the reason why China's population is now going into decline. The least-developed region is Sub-Saharan Africa, where fertility rates remain close to pre-industrial levels in some countries. As these countries transition, they will undergo significant rates of population growth.