Fhir Patient gender and AdministrativeGender clarification

Two questions related to the gender field in the Patient Resource

  1. Why is the gender field only a string not a CodeableConcept?
  2. How is the AdministrativeGender element used? I do not see any other Fhir Resource referencing it.

a vast majority of all healthcare systems support just the simple genders male, female, unknown, and other, or some subset of those. Making the gender a full CodeableConcept is much harder work for anyone reading resources, and only relevant in very few cases. Hence, implementers can provide an extension (to clarify the meaning of ‘other’, usually).

For the ‘the AdministrativeGender element’ - are you asking about the ValueSet here? If so, where it used is linked from that page. Otherwise, what are you referring to?

Thanks. The explanation helps.
So my understanding here is that the AdministrativeGender defines a collection of valid string values that can be set for the gender field. But the field itself will still be stored as a string.

yes it defines a collection of valid string values. And if you want to store it that way, you can, but some people store it as an enum integer, or a key reference to the source definition (Storage is not what FHIR specifies)