UAB

Unassigned At Birth (UAB or UAAB), also seen as GUAB/SUAB (Gender/Sex Undesignated At Birth) or UGAB/USAB (Unassigned Gender/Sex At Birth) refers to someone who does not have an assigned at birth. It is most commonly designated with the letter "U". It is most commonly used by parents who are raising their children without a prescribed gender.