ISO/IEC 5218 Information technology — Codes for the representation of human sexes is an international standard

International standard

International standards are standards developed by international standards organizations. International standards are available for consideration and use, worldwide...

 that defines a representation of human sexes through a language-neutral single-digit code. It can be used in information systems such as database

Database

A database is an organized collection of data for one or more purposes, usually in digital form. The data are typically organized to model relevant aspects of reality , in a way that supports processes requiring this information...

 applications.

The four codes specified in ISO/IEC 5218 are:

• 0 = not known,
• 1 = male,
• 2 = female,
• 9 = not applicable.

The standard specifies that its use may be referred to by the designator "SEX".

The standard explicitly states that no significance is to be placed on the fact that male is encoded as 1 and female as 2. The encoding merely reflects existing practice in the countries that initiated this standard.

ISO/IEC 5218 was created by ISO

International Organization for Standardization

The International Organization for Standardization , widely known as ISO, is an international standard-setting body composed of representatives from various national standards organizations. Founded on February 23, 1947, the organization promulgates worldwide proprietary, industrial and commercial...

's Data Management and Interchange Technical Committee, proposed in November 1976, and updated in July 2004.

This standard is used in several national identification number

National identification number

A national identification number, national identity number, or national insurance number is used by the governments of many countries as a means of tracking their citizens, permanent residents, and temporary residents for the purposes of work, taxation, government benefits, health care, and other...

s. For example, the first digit of the French INSEE

INSEE code

The INSEE code is a numerical indexing code used by the French National Institute for Statistics and Economic Studies to identify various entities, including communes, départements...

 number, the first digit of the Republic of China

Republic of China

The Republic of China , commonly known as Taiwan , is a unitary sovereign state located in East Asia. Originally based in mainland China, the Republic of China currently governs the island of Taiwan , which forms over 99% of its current territory, as well as Penghu, Kinmen, Matsu and other minor...

 national identification card

Republic of China National Identification Card

The National Identification Card is an identity document issued only to citizens of the Republic of China that have a household registration in the Taiwan area...

 (Chinese: 中華民國國民身分證) are based on ISO/IEC 5218 values.