The sex ratio refers to the:

NCERT (2025-26): “2.1 Some Theories and Concepts in Demography … The sex ratio refers to the number of females per 1000 males in a given area at a specified time period. Historically, all over the world it has been found that there are slightly more females than males in most countries. This is despite the fact that, slightly more male babies are born than female ones; nature seems to produce roughly 943 to 952 female babies for every 1000 males.…”