As India’s fertility rate falls, what does replacement fertility really mean?

India's population growth story has shifted from rapid expansion to a decline in birth rates. Nithin Kamath, co-founder of Zerodha, shared projections that every state in India could fall below replacement fertility by 2039, with Bihar being the last to reach this point. Replacement fertility is defined as the average number of children needed per woman for one generation to replace the preceding generation, which is around 2.1 children per woman in most societies.

Falling below this threshold does not immediately cause population decline, as it also depends on age structure, mortality, and migration. The factors contributing to the declining fertility rate in India include increased education, access to contraception, urbanization, delayed marriage, and changing aspirations. These trends are evident in metropolitan areas, where couples often prioritize career stability and financial independence, leading to smaller family sizes.

However, a lower total fertility rate (TFR) does not indicate whether individuals are "succeeding" or "failing" at having children, as it is merely a statistical measure of average childbearing across a population. Infertility, on the other hand, is a medical condition involving difficulty conceiving when a pregnancy is desired. The terms should not be conflated.