Keep it named gender because "birthSex" has a more precise definition and gender acknowledges the ambiguity Add comment that Lloyd recommended: "This element should ideally reflect whether the individual is genetically masculine or feminine. However, as reported information based on the knowledge of the patient or reporting friend/relative, there may be situations where the reported gender might not be totally accurate. E.g. 'Aunt Sue' might be XY rather than XX. Questions soliciting this information should be phrased to encourage capture of genetic gender where known. However, systems performing analysis should also allow for the possibility of imprecision with this element"