I disagree with my director?

I recently was cast in Aladdin as the role of the genie despite the fact that I am a girl. When auditioning, I was under the impression that the genie's gender would be changed from a man to a woman, or at least a more feminine man. Instead, I am expected to wear a suit with a twelve pack and a goatee, talk like a man and act like a man. This would be no problem, but the director is insisting I still sing in the falsetto octave, knowing I can't sing in a man's octave. I'm going to look like an idiot and I have no idea what to do.