This is the ValueSet that contains all the codes in Administrative Gender (HL7 V3) (http://cts.nlm.nih.gov/fhir/ValueSet/2.16.840.1.113883.1.11.1) and Federal Administrative Sex (http://cts.nlm.nih.gov/fhir/ValueSet/2.16.840.1.113762.1.4.1021.121). E.g. what you have to deal with if you get resources containing codes in either of them