Originally Posted by
LordVargK
Why does he/she/it have a gender anyways?
It's not like it's a living being. The arbiter won't ever reproduce. The binary distinction between male and female only applies to most higher animals (humans included), because that was nature's way of ensuring optimal evolution.
In WoW, most (all?) living beings were created by the titans and cursed by the old gods. Somewhere along the way lies the explanation for sexual dimorphism on Azeroth, but I don't think there's a canon explanation for it.
But why the arbiter should have a gender will probably never adressed in lore. It should be "it", but it's humanoid looking. And that is the problem:
Everything that resembles a human will be classified by its appearance first: Has it boobs? Yes? Okay, "she". No? "He". If it's not clear, then gender is determinded by voice. Now, does the arbiter look very feminin? Arguably so, but not definitly. So assigning a gender to something very androgyn looking makes really no sense at first glance, but I'm sure the arbiter will be voiceacted, so it has to have a gender (or player instictively give it one, based on it's voice). Meaning, its gender will have absolutely no effect and was just chosen based on the voice it is given.
That means, that Arbiter (generic masculine) is its name, because its gender does not matter at all for anything other than voiceacting (and because humans will always categorize something humanoid into male or female).