description: A code classifying the person's sex assigned at birth. This extension aligns with LOINC 76689-9 (Sex assigned at birth). package_name: rs/hl7.fhir.us.core derivation: constraint name: USCoreBirthSexExtension type: Extension elements: url: pattern: {type: uri, value: 'http://hl7.org/fhir/us/core/StructureDefinition/us-core-birthsex'} type: uri index: 0 value: choices: [valueCode] index: 2 valueCode: {type: code, choiceOf: value, index: 3} package_version: 8.0.0 class: extension kind: complex-type url: http://hl7.org/fhir/us/core/StructureDefinition/us-core-birthsex base: http://hl7.org/fhir/StructureDefinition/Extension version: 8.0.0 required: [value, valueCode]