@prefix : <foo://bla/>.
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>.
@prefix owl: <http://www.w3.org/2002/07/owl#>.
:Male a owl:Class.      ## if these lines are missing,
:Female a owl:Class.    ## the reasoner complains
:Person owl:equivalentClass [ owl:unionOf (:Male :Female) ].
:EqToPerson owl:equivalentClass [ owl:unionOf (:Female :Male) ].
:unknownPerson a [ owl:unionOf (:Female :Male) ].