http://hl7.org/fhir/StructureDefinition/patient-genderIdentity|5.2.0

The gender the patient identifies with. The Patient's gender identity is used as guidance (e.g. for staff) about how to interact with the patient.
typedestination
baseDefinitionhttp://hl7.org/fhir/StructureDefinition/Extension
typehttp://hl7.org/fhir/StructureDefinition/Extension
Extension.value[x].typehttp://hl7.org/fhir/StructureDefinition/CodeableConcept