Sex (SEXP)

This variable records each person’s sex. A person's sex is based on their sex characteristics, such as their chromosomes, hormones and reproductive organs. If sex is not stated it is imputed.

See also, Imputation flag for sex (IFSEXP).

All persons

Responses to the sex question are captured from mark box responses on the form so the risk of processing error is minimal. Male, female and non-binary sex are the three options. A person can select one response only or they can select more than one response (male and non-binary sex, or female and non-binary sex). The online Census form allows respondents who select the non-binary sex response to provide further information. This field is optional and can be used to describe the circumstances specific to the person responding.

Note that data collected from the sex question will be reported in most Census data releases as ‘male’ or ‘female’ in order to maintain the quality of standard products at the small area level. Where a respondent has provided a male or female response and a non-binary sex response, the male or female response will be used to determine a binary sex variable. Otherwise, sex will be derived by a statistical process using random allocation.

Binary sex is also imputed when the question is not answered. If sex is missing on partially completed forms, it is imputed by automated and manual coding processes using relevant information provided on the incomplete form. For records that could not be resolved through this process, sex is derived by a statistical process using random allocation. For more information about imputation, please see imputation in the Census glossary.

The Imputation flag for sex (IFSEXP) variable indicates if a person's sex was imputed in the Census.

A question on sex has been asked at every Census since 1911.

In 2016, respondents had the option to respond as 'other sex'. If a person wanted to identify as other than male or female, they were instructed to call the Census Inquiry Service for information on how to identify on Census forms. To respond online, they were given specific login details to access an alternate form which allowed them to select 'other' and enter in information in a 'please specify' text box. To respond on a paper form, they were instructed to write on the right-hand side of the response area and these were checked manually to record a respondent's 'other sex' category. 

In 2021, a ‘non-binary sex’ option was added as an input category to the standard question, however the output categories for this variable are unchanged for 2021.

The question on the Census asks about a person’s sex, which is based on their sex characteristics, such as their chromosomes, hormones and reproductive organs.

Respondents were instructed to answer in the way that applies to them, with the guidance that the non-binary sex category was included to provide an option for people who are not exclusively male or female, for example people with variations in sex characteristics or who are intersex.

Feedback from respondents and members of the LGBTIQ+ community during Census enumeration identified some confusion on how to answer the question for people who are gender diverse, gender non-binary or transgender. It is therefore likely that some respondents answered based on their gender identity rather than their biological sex. Research undertaken by the ABS in developing the sex question for the Census suggests that this was also the case in previous censuses. This is not able to be quantified for respondents who selected a binary sex response, for example a person born male but living as a woman for many years may select ‘female’ as their response, noting this may be balanced out with respondents who were born female but living as a man and selecting ‘male’ as their response.

The ABS has released some analysis of the responses to ‘non-binary sex’ in an analytical article. To view the article visit Analysis of non-binary sex responses. While this article outlines some of the ways this group responded to the sex question, it also highlights the limitations of collecting data in this way. For more information see also Non-binary sex in the 2021 Census.

Using the Imputation Flag for Sex (IFSEXP), the non-response rate for Sex (SEXP) was 4.7% in 2021. This is a decrease from 5.8% in 2016. 

• Imputation flag for sex (IFSEXP)
• Derivation
• Hotdecking
• Imputation
• Non-binary sex
• Visitors to Australia

• Population
• People and communities
• Standard for Sex, Gender, Variations of Sex Characteristics and Sexual Orientation Variables
• Population: Census