The foaf:gender property relates a foaf:Agent (typically a foaf:Person) to a string representing its gender. In most cases the value will be the string 'female' or 'male' (in lowercase without surrounding quotes or spaces. Like all FOAF properties, there is in general no requirement to use foaf:gender in any particular document or description. Values other than 'male' and 'female' may be used, but are not enumerated here. The foaf:gender mechanism is not intended to capture the full variety of biological, social and sexual concepts associated with the word 'gender'.

Anything that has a foaf:gender property will be some kind of foaf:Agent. However there are kinds of foaf:Agent to which the concept of gender isn't applicable (eg. a foaf:Group. FOAF does not currently include a class corresponding directly to "the type of thing that has a gender".

Note that FOAF's notion of gender isn't defined biologically or anatomically - this would be tricky since we have a broad notion that applies to all foaf:Agents (including robots etc.; Bender from Futurama is 'male', for example). As stressed above, FOAF's notion of gender doesn't attempt to encompass the full range of concepts associated with the human gender, biology and sexuality. As such it is a (perhaps awkward) compromise between the clinical and the social/psychological. In general, a person will be the best authority on their foaf:gender. Feedback on this design is particularly welcome (via the FOAF mailing list, rdfweb-dev). We have tried to be respectful of diversity without attempting to catalogue or enumerate that diversity.

This may also be a good point for a periodic reminder: as with all FOAF properties, documents that use it will on occassion be innacurate, misleading or outright false. FOAF, like all open means of communication, supports lying. Application authors using FOAF data should be cautious in their presentation of all unverified information, but be particularly sensitive to issues and risks surrounding sex and gender. Designers of FOAF-based user interfaces should be careful to allow users to omit foaf:gender when describing themselves and others, and to allow at least for values other than 'male' and 'female' as options. Users of information conveyed via FOAF (as via information conveyed through mobile phone text messages, email, Internet chat, HTML pages etc.) should be skeptical of unverified information.