description: A code classifying the person's sex assigned at birth  as specified by the [Office of the National Coordinator for Health IT (ONC)](https://www.healthit.gov/newsroom/about-onc). This extension aligns with the C-CDA Birth Sex Observation (LOINC 76689-9).
package_name: hl7.fhir.us.core
derivation: constraint
name: US Core Birth Sex Extension
type: Extension
elements:
  url:
    pattern: {type: Uri, value: 'http://hl7.org/fhir/us/core/StructureDefinition/us-core-birthsex'}
    index: 0
  valueCode: {type: code, index: 1}
package_version: 1.1.0
class: extension
kind: complex-type
url: http://hl7.org/fhir/us/core/StructureDefinition/us-core-birthsex
base: http://hl7.org/fhir/StructureDefinition/Extension
version: 1.1.0