Sex at birth of person

Status: This standard was approved as a departmental standard on July 31, 2026.

Definition

Sex at birth refers to the sex assigned at birth, as recorded on a person's birth registration. It generally reflects their physical characteristics and reproductive system.

Person refers to an individual and is the unit of analysis for most social statistics programs.

Usage

Sex at birth is a distinct concept from gender, although they are closely related. Sex at birth is primarily defined based on a person's physical characteristics and reproductive system. In contrast, gender is a multidimensional concept influenced by several additional factors, including cultural and behavioural norms, as well as individual experiences and characteristics.

These concepts are related because children are most often raised as boys or girls based on their sex at birth, linking the concepts of gender identity and expression to sex at birth. This alignment between sex at birth and gender reflects what is generally observed in the broader population.

For most people, their sex at birth corresponds to their gender (cisgender men and cisgender women). However, for some people, their sex at birth and gender do not align (transgender men and transgender women), or their gender is not exclusively a man nor a woman (non-binary people).

Therefore, caution should be exercised when comparing counts for the sex at birth variable with those for the gender variable. For example, in a given population, the group of persons of female sex (sex at birth) does not necessarily correspond to the group of women (gender), although the two groups are generally very similar, given the relatively small size of the transgender and non-binary populations according to 2021 Census data.

The variable 'gender of person' is used in most social statistics programs at Statistics Canada, in accordance with the Treasury Board of Canada Secretariat's "Policy Direction to Modernize the Government of Canada's Sex and Gender Information Practices", adopted in 2018.

The variable 'sex at birth of person' can be used where information on sex at birth is needed, for example, for measuring some demographic and physical health indicators. It can also be used in conjunction with the variable 'gender of person' to estimate the transgender population. These two variables can also be used, together with the variable 'sexual orientation of person', to estimate the sexual and gender diverse population, which is often represented by the 2SLGBTQ+ acronym. This acronym refers to people who are Two-Spirit, lesbian, gay, bisexual, transgender and queer, as well as those who use other terms related to sexual or gender diversity.

Conformity to relevant internationally recognized standards

This standard is broadly compatible with the recommendations for censuses contained in the United Nations Economic Commission for Europe Conference of European Statisticians (UNECE-CES) "Recommendations for the 2030 Round of Population and Housing Censuses", 2025. The UNECE-CES publication (section 15.2) includes the collection of sex as a core topic and defines it as relating to "biological attributes that result in one being labelled as male or female". It indicates that the sex (male or female) of every individual should be recorded in the census or obtained from the appropriate administrative record. It also notes that some countries are moving from collecting information on sex to collecting information on gender. However, it does not specify whether sex refers to sex at birth.

This standard is also broadly compatible with the definitions of sex at birth published by Statistics New Zealand in the "Data standard for gender, sex, and variations of sex characteristics", 2021, and by the Australian Bureau of Statistics in "Standard for Sex, Gender, Variations of Sex Characteristics and Sexual Orientation Variables", 2021, both national statistical agencies with which Statistics Canada shares several similarities in terms of roles and functions.

Statistics New Zealand defines sex at birth as "the sex recorded at a person's birth (for example, what was recorded on their birth certificate)." The Australian Bureau of Statistics also defines it as sex recorded at birth, which "refers to what was determined by sex characteristics observed at birth or infancy."

Classifications

• Classification of sex at birth October 01, 2021 to current

Additional information

Reference guides

• Gender of Person Reference Guide
• Sex at Birth of Person Reference Guide

See:

• Gender of person

Relation to previous version

• Sex at birth of person July 31, 2026 to current

  The wording of the definition of sex at birth has been slightly modified. The variant classification of sex at birth has been removed.

• Sex at birth of person October 01, 2021 to July 30, 2026

  The name of the concept has been changed from 'sex' to 'sex at birth', and the definitions in the categories of both classifications have been modified.

• Sex of person January 25, 2018 to September 30, 2021

  This standard updates the definition by specifying that sex refers to sex at birth typically assigned based on a person's reproductive system and other physical characteristics. This standard also provides a classification variant of sex that recognizes the 'intersex' category. Alpha codes are provided for categories in both classifications presented in this standard.

• Sex of person May 22, 2007 to January 24, 2018

  This was the departmental standard from May 22, 2007 to January 24, 2018.