In population ecology and demography, the net reproduction rate, R0, is the average number of offspring (often specifically daughters) that would be born to a female if she passed through her lifetime conforming to the age-specific fertility and mortality rates of a given year. This rate is similar to the gross reproduction rate but takes into account that some females will die before completing their childbearing years. An R0 of one means that each generation of mothers is having exactly enough daughters to replace themselves in the population. [1] [2] If the R0 is less than one, the reproductive performance of the population is below replacement level.[ citation needed ]
The R0 is particularly relevant where sex ratios at birth are significantly affected by the use of reproductive technologies, or where life expectancy is low.[ citation needed ]
The current (2015–20) estimate for the R0 worldwide under the UN's medium variant model is 1.09 daughters per woman. [3]
India is the most populous country in the world with one-sixth of the world's population. According to estimates from the United Nations (UN), India has overtaken China as the country with the largest population in the world, with a population of 1,425,775,850 at the end of April 2023.
The demographics of Mozambique describes the condition and overview of Mozambique's peoples. Demographic topics include basic education, health, and population statistics as well as identified racial and religious affiliations.
Demographic features of the population of Zambia include population density, ethnicity, education level, health of the populace, economic status, religious affiliations and others aspects of the population.
Demography is the statistical study of human populations: their size, composition, and how they change through the interplay of fertility (births), mortality (deaths), and migration.
In vitro fertilisation (IVF) is a process of fertilisation where an egg is combined with sperm in vitro. The process involves monitoring and stimulating a woman's ovulatory process, removing an ovum or ova from their ovaries and letting a man's sperm fertilise them in a culture medium in a laboratory. After the fertilised egg (zygote) undergoes embryo culture for 2–6 days, it is transferred by catheter into the uterus, with the intention of establishing a successful pregnancy.
Family planning is the consideration of the number of children a person wishes to have, including the choice to have no children, and the age at which they wish to have them. Things that may play a role on family planning decisions include marital situation, career or work considerations, financial situations. If sexually active, family planning may involve the use of contraception and other techniques to control the timing of reproduction.
Fertility is the ability to conceive a child. The fertility rate is the average number of children born during an individual's lifetime and is quantified demographically. Conversely, infertility is the difficulty or inability to reproduce naturally. In general, infertility is defined as not being able to conceive a child after one year of unprotected sex. Because infertility is widespread, fertility specialists all over the world assist persons and couples who experience difficulties conceiving a baby.
Birth rate, also known as natality, is the total number of live human births per 1,000 population for a given period divided by the length of the period in years. The number of live births is normally taken from a universal registration system for births; population counts from a census, and estimation through specialized demographic techniques. The birth rate is used to calculate population growth. The estimated average population may be taken as the mid-year population.
The Total Fertility Rate (TFR) of a population is the average number of children that are born to a woman over her lifetime if:
Sub-replacement fertility is a total fertility rate (TFR) that leads to each new generation being less populous than the older, previous one in a given area. The United Nations Population Division defines sub-replacement fertility as any rate below approximately 2.1 children born per woman of childbearing age, but the threshold can be as high as 3.4 in some developing countries because of higher mortality rates. Taken globally, the total fertility rate at replacement was 2.33 children per woman in 2003. This can be "translated" as 2 children per woman to replace the parents, plus a "third of a child" to make up for the higher probability of males born and mortality prior to the end of a person's fertile life. In 2020, the global average fertility rate was around 2.4 children born per woman.
Fecundity is defined in two ways; in human demography, it is the potential for reproduction of a recorded population as opposed to a sole organism, while in population biology, it is considered similar to fertility, the natural capability to produce offspring, measured by the number of gametes (eggs), seed set, or asexual propagules.
Population momentum is a consequence of the demographic transition. Population momentum explains why a population will continue to grow even if the fertility rate declines. Population momentum occurs because it is not only the number of children per woman that determine population growth, but also the number of women in 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. Population momentum usually occurs in populations that are growing.
In population biology and demography, generation time is the average time between two consecutive generations in the lineages of a population. In human populations, generation time typically has ranged from 20 to 30 years, with wide variation based on gender and society. Historians sometimes use this to date events, by converting generations into years to obtain rough estimates of time.
The ageing of Europe, also known as the greying of Europe, is a demographic phenomenon in Europe characterised by a decrease in fertility, a decrease in mortality rate, and a higher life expectancy among European populations. Low birth rates and higher life expectancy contribute to the transformation of Europe's population pyramid shape. The most significant change is the transition towards a much older population structure, resulting in a decrease in the proportion of the working age while the number of the retired population increases. The total number of the older population is projected to increase greatly within the coming decades, with rising proportions of the post-war baby-boom generations reaching retirement. This will cause a high burden on the working age population as they provide for the increasing number of the older population.
The gross reproduction rate (GRR) is the average number of daughters a woman would have if she survived all of her childbearing years, which is roughly to the age of 45, subject to the age-specific fertility rate and sex ratio at birth throughout that period. This rate is a measure of replacement fertility if mortality is not in the equation. It is often regarded as the extent to which the generation of daughters replaces the preceding generation of women and so on and so forth. If the value is equal to one that indicates that women will replace themselves. If the value is more than one that indicates that the next generation of women will outnumber the current one. If the value is less than one that indicates that the next generation of women will be less numerous than the current one.
Family planning in India is based on efforts largely sponsored by the Indian government. From 1965 to 2009, contraceptive usage has more than tripled and the fertility rate has more than halved, but the national fertility rate in absolute numbers remains high, causing concern for long-term population growth. India adds up to 1,000,000 people to its population every 20 days. Extensive family planning has become a priority in an effort to curb the projected population of two billion by the end of the twenty-first century.
Earth has a human population of over 8 billion as of 2024, with an overall population density of 50 people per km2. Nearly 60% of the world's population lives in Asia, with almost 2.8 billion in the countries of China and India combined. The percentage shares of China, India and rest of South Asia of the world population have remained at similar levels for the last few thousand years of recorded history. The world's literacy rate has increased dramatically in the last 40 years, from 66.7% in 1979 to 86.3% today. Lower literacy levels are mostly attributable to poverty. Lower literacy rates are found mostly in South Asia and Sub-Saharan Africa.
Fertility factors are determinants of the number of children that an individual is likely to have. Fertility factors are mostly positive or negative correlations without certain causations.