Fertility rate in the context of "Human population projections"

As of 2025, Afghanistan has an estimated population of around 49.5 million people. The country is characterized by a highly diverse, multi-ethnic, and multilingual society, reflecting its historical position at the crossroads of Central, South, and Western Asia, along ancient trade and invasion routes. The four major ethnic categories in the country are Pashtun, Tajik/Farsiwan, Hazara, and Uzbek. In addition, Afghanistan has a plethora of minor ethnic categories, including Turkmen, Baloch, Aimaq, Nuristani, Arab and many others. Together they make up the contemporary Afghan people.

Approximately 43% of the population was under the age of 15, and about 74% of Afghans lived in rural areas as of 2016. The country has one of the highest fertility rates in the world outside of Africa, with the average woman giving birth to five children over her lifetime. Around 6.8% of infants die during childbirth or early infancy. According to the World Health Organization (WHO), the nation's average life expectancy was estimated at about 63 years as of 2019. The prevalence of HIV remains very low, affecting only about 0.04% of the population.

Population momentum or demographic inertia is the tendency of the raw birth rate to rise as a result of past high fertility rates, even after fertility rates have fallen, or vice-versa. This occurs because a current increase in fertility rates causes an increase in the number of women of childbearing age roughly twenty-to-forty years later, meaning population growth figures tend to lag substantially behind fertility rates. Well-known examples include the Echo Boom (the increase in the total number of births as baby boomers reached child-rearing age) and Chinese population growth throughout the era of the one-child policy (from 1979 until 2021).

Population momentum explains why a population will continue to grow even if the fertility rate declines or continues to decline even if the fertility rate grows. Population momentum occurs because it is not only the number of children per woman that determine population growth, but also the number of women of reproductive age. Eventually, when the fertility rate reaches the replacement rate and the population size of women in the reproductive age bracket stabilizes, the population achieves equilibrium and population momentum comes to an end. Population momentum is defined as the ratio of the size of the population at that new equilibrium level to the size of the initial population.

Fertility in colloquial terms refers the ability to have offspring. In demographic contexts, fertility refers to the actual production of offspring, rather than the physical capability to reproduce, which is termed fecundity. The fertility rate is the average number of children born during an individual's lifetime. In medicine, fertility refers to the ability to have children, and infertility refers to difficulty in reproducing naturally. In general, infertility or subfertility in humans is defined as not being able to conceive a child after one year (or longer) of unprotected sex. The antithesis of fertility is infertility, while the antithesis of fecundity is sterility.

Demographic features of the population of Lithuania include population density, ethnicity, level of education, health, economic status, and religious affiliations.

The population of Lithuania increased after the end of World War II, reaching its apex in 1991 with 3.7 million, but started to decline after the Dissolution of the Soviet Union later that year, which negatively impacted the country. As social problems ensued after the dissolution of the Soviet Union, the birth rate decreased and the population fell sharply due to a relatively high death rate, mass emigration and a large increase of its suicide rate that made Lithuania one of the countries with the highest suicide rates in the world. This caused its population to drop below 3 million in 2012, losing over a quarter of its population in 30 years. As of today, Lithuania's fertility rate is one of the lowest in the world. However, while its suicide rate would remain the highest in the European Union, it dropped over time, and in the 2020's, the Lithuanian population would return to grow slightly due to immigration and a decreasing death rate.

Income and fertility is the association between monetary gain on one hand, and the tendency to produce offspring on the other. There is generally an inverse correlation between income and the total fertility rate within and between nations. The higher the degree of education and GDP per capita of a human population, subpopulation or social stratum, the fewer children are born in any developed country. In a 1974 United Nations population conference in Bucharest, Karan Singh, a former minister of population in India, illustrated this trend by stating "Development is the best contraceptive." In 2015, this thesis was supported by Vogl, T.S., who concluded that increasing the cumulative educational attainment of a generation of parents was by far the most important predictor of the inverse correlation between income and fertility based on a sample of 48 developing countries.

Generally a developed country has a lower fertility rate while a less economically developed country has a higher fertility rate. For example the total fertility rate for Japan, a developed country with per capita GDP of US$32,600 in 2009, was 1.22 children born per woman. But total fertility rate in Ethiopia, with a per capita GDP of $900 in 2009, was 6.17 children born per woman.

As of 2025, the world's core Jewish population (those identifying as Jews to the exclusion of all else) was estimated at 15.8 million, which is approximately 0.2% of the 8 billion worldwide population. However, the "core Jewish" criterion faces criticism, especially in debates over the American Jewish population count, since it excludes the growing number of people who carry multiple ethnic and religious identities who may self-identify as Jews or qualify as Jewish under the Halakhic principle of matrilineal descent. Israel and the US host the largest Jewish populations of 7.42 million and 7.46 million respectively. Other countries with core Jewish populations above 100,000 include France (440,000), Palestine (432,800), Canada (398,000), the United Kingdom (312,000), Argentina (171,000), Russia (132,000), Germany (125,000), and Australia (117,200). In 1939, the core Jewish population reached its historical peak of 16.6 million or more. Due to the murder of almost six million Jews during the Holocaust, this number was reduced to 11 million by 1945. The core Jewish population grew to around 13 million by the 1970s and then recorded almost no growth until around 2005, due to low fertility rates and interfaith marriage by Jews. From 2005 to 2018, the world's core Jewish population grew 0.63% annually on average, while the world's population overall grew 1.1% annually in the same period. This increase primarily reflects rapid growth of Haredi, Orthodox populations.

Sources disagree as to the current population of Eritrea, with some proposing numbers as low as 3.6 million and others as high as 6.7 million. Eritrea has never conducted an official government census.

The nation has nine recognized ethnic groups. Of these, the largest is the Tigrinya, who make up around 50% of the population; the Tigre people, who also speak Semitic languages, constitute around 30% of residents. Most of the rest of the population belong to other Afro-Asiatic-speaking communities of the Cushitic branch. Additionally, there are a number of Nilo-Saharan-speaking ethnic minorities and other smaller groups.