Explain the term “replacement fertility

Replacement fertility is a term used in demography to refer to the total fertility rate at which a population exactly replaces itself from one generation to the next, without migration. This rate is roughly 2.1 children per woman for most countries, although it may modestly vary with mortality rates.

Here are the steps to understand this concept:

1. Understand the term 'fertility rate': Fertility rate is the average number of children a woman gives birth to in her child-bearing years (usually considered to be between the ages of 15 to 49).

2. Understand 'total fertility rate': This is the average number of children a woman would have assuming that current age-specific birth rates remain constant throughout her child-bearing years.

3. Understand 'replacement': In this context, replacement refers to a situation where the number of births equals the number of deaths, so the population size remains stable.

4. Put it all together: So, replacement fertility is the total fertility rate—the average number of children born per woman—at which a population replaces itself from one generation to the next, without needing to rely on immigration. This is typically around 2.1 children per woman. The extra .1 accounts for children who may not survive to reproductive age.

5. Understand the implications: If the replacement fertility rate is less than 2.1, the population will decrease (assuming no immigration). If it's greater than 2.1, the population will increase. This concept is important for understanding population dynamics and predicting future population trends.