The classification is phenotypical rather than genotypical, i.e. it does not provide codes for medical or scientific purposes.

Note that "0 Not Known" means that the sex of a PERSON has not been recorded. "9 Not Specified" means indeterminate, i.e. unable to be classified as either male or female.

National Codes:

References:
The e-GIF version approved for use in NHS England is:
Government Data Standards Catalogue: (GDSC), Version 2.0, Agreed 11 September 2003.
Further information can be found on the Cabinet Office website.

This attribute is also known by these names:

Context	Alias
plural	PERSON GENDER CODES