The ‘Sex’ variable in the 2021 Census is based on a person’s sex characteristics, such as their chromosomes, hormones and reproductive organs (ABS 2022b). While typically based upon the sex characteristics observed and recorded at birth or infancy, a person's sex can change over the course of their lifetime and may differ from their sex recorded at birth (AIHW 2022). For more information on the ‘Sex’ variable in the 2021 Census, see Sex (SEXP)