gender identity disorder (EFO_0008587, an Experimental Factor Ontology id) is a disorder characterized by a strong and persistent cross-gender identification (such as stating a desire to be the other sex or frequently passing as the other sex) coupled with persistent discomfort with his or her sex (manifested in adults, for example, as a preoccupation with altering primary and secondary sex characteristics through hormonal manipulation or surgery). [ NCI ].