High Quality Content by WIKIPEDIA articles! The net reproduction rate is the average number of 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 NRR of one means that each generation of mothers is having exactly enough daughters to replace themselves in the population. The NRR is particularly relevant where sex ratios at birth are significantly affected by the use of reproductive technologies, or where life expectancy is low.