The age-specific fertility rate is the number of children born per woman per year for women at a specified age. Integrating over a lifetime gives a metric called the total fertility rate, which is the average number of children that a woman would have if all the age-specific fertility rates stayed constant.

Globally, the total fertility rate was 2.49 children per woman in 2015, down from 5.05 in 1950. This large decline is part of what is known as the demographic transition from high birth rates and high child mortality to low birth rates and low child mortality. The causes of this include more women in education and work, as well as greater access to contraception.

A recent study by researchers at the University of Washington's Institute for Health Metrics and Evaluation extrapolates trends in education and contraception access and predicts that this decline in fertility rates will continue, reaching 1.33-2.08 in 2100.

What will the global total fertility rate be in 2050?

Resolution will be by the figure for the year 2050 published by the UN Population Division or other appropriate branch of the UN/WHO in the first edition released after 2050. If a figure is only available for a range of time of no more than 5 years that includes 2050, resolve at that value. If no such figures are available, then resolve ambiguously.