India is the second most populated country in the world with a sixth of the world's population. According to official estimates in 2022, India's population stood at over 1.4 billion. According to UN forecasts, in 2023 India will overtake China and become the most populous country in the world.
Demography is the statistical study of populations, especially human beings.
The United States had an official estimated resident population of 333,287,557 on July 1, 2022, according to the U.S. Census Bureau. This figure includes the 50 states and the District of Columbia but excludes the population of five unincorporated U.S. territories as well as several minor island possessions. The United States is the third most populous country in the world. The Census Bureau showed a population increase of 0.4% for the twelve-month period ending in July 2022, below the world average annual rate of 0.9%. The total fertility rate in the United States estimated for 2021 is 1.664 children per woman, which is below the replacement fertility rate of approximately 2.1.
In demography, demographic transition is a phenomenon and theory which refers to the historical shift from high birth rates and high death rates in societies with minimal technology, education and economic development, to low birth rates and low death rates in societies with advanced technology, education and economic development, as well as the stages between these two scenarios. Although this shift has occurred in many industrialized countries, the theory and model are frequently imprecise when applied to individual countries due to specific social, political and economic factors affecting particular populations.
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.
A baby boom is a period marked by a significant increase of birth rate. This demographic phenomenon is usually ascribed within certain geographical bounds of defined national and cultural populations. People born during these periods are often called baby boomers. The cause of baby booms involves various fertility factors. The best-known baby boom occurred in the mid-twentieth century, sometimes considered to have started after the end of the Second World War, sometimes from the late 1930s, and ending in the 1960s.
Fertility is the ability to conceive a child. The fertility rate is the average number of children born during an individuals 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. Infertility is widespread, with fertility specialists available all over the world to assist parents and couples who experience difficulties conceiving a baby.
The birth rate for a given period is the total number of live human births per 1,000 population 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 would be born to a woman over her lifetime if:
- she were to experience the exact current age-specific fertility rates (ASFRs) through her lifetime
- she were to live from birth until the end of her reproductive life.
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 average global fertility rate was around 2.4 children born per woman.
A population decline in humans is a reduction in a human population size. Over the long term, stretching from prehistory to the present, Earth's total human population has continued to grow; however, current projections suggest that this long-term trend of steady population growth may be coming to an end.
The middle of the 20th century was marked by a significant and persistent increase in fertility rates in many countries of the world, especially in the Western world. The term baby boom is often used to refer to this particular boom, generally considered to have started immediately after World War II, although some demographers place it earlier or during the war. This terminology led to those born during this baby boom being nicknamed the baby boomer generation.
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."
Reproductive endocrinology and infertility (REI) is a surgical subspecialty of obstetrics and gynecology that trains physicians in reproductive medicine addressing hormonal functioning as it pertains to reproduction as well as the issue of infertility. While most REI specialists primarily focus on the treatment of infertility, reproductive endocrinologists are trained to also test and treat hormonal dysfunctions in females and males outside infertility. Reproductive endocrinologists have specialty training (residency) in obstetrics and gynecology (ob-gyn) before they undergo sub-specialty training (fellowship) in REI.
The relationship between fertility and intelligence has been investigated in many demographic studies. There is evidence that, on a population level, measures of intelligence such as educational attainment and literacy are negatively correlated with fertility rate in some contexts. However, genetic studies have shown no evidence for dysgenic effects in human populations. Theories about dysgenic and eugenic effects in human populations have historically been associated with scientific racism.
Population projections are attempts to show how the human population statistics might change in the future. These projections are an important input to forecasts of the population's impact on this planet and humanity's future well-being. Models of population growth take trends in human development, and apply projections into the future. These models use trend-based-assumptions about how populations will respond to economic, social and technological forces to understand how they will affect fertility and mortality, and thus population growth.
Fertility fraud is the failure on the part of a fertility doctor to obtain consent from a patient before inseminating her with his own sperm. This normally occurs in the context of people using assisted reproductive technology (ART) to address fertility issues.
