Paul Davidson (on behalf of the UK government) endorses the use of the ISO codes. Danny Delcambre (Eurostat) suggests we use the list provided by Eurostat which is very similar to the one in the spec at the moment (codes one can easily map to ISO 5218 + 1 extra).
It is the for the WG to decide on the course of action to follow.
Michel van Meteren, expert at the Dutch Tax Service, send me comments via e-mail (in Dutch) in favour of sticking to ISO 5218.
Gender should not necessarily be restricted to one code list. To solve this, a gender code should indicate to which code list it belongs. This can be achieved, for instance, by making Code a Complex Data Type (a Concept).
The UN/CEFACT Core Data Type Library can be a source of inspiration here. A data type Code could include the following attributes:
In a Linked Data World, the following additional properties could be useful: