Though there are a very real physical difference between males and females, what is there to say that there cant be mental/psychological differences aswell.
No matter the case, though, I tend to expect us humans to act well above primlitive and instinctual behaviour due to our evolved intelligence and in principle we could adapt just and rational ideas over primitive and traditional ones.
There should be no reason for a male fighter pilot to acknowledge female voices over male, but IF he does for whatever reason, its better to put a female voice in the ships warning system.
I never said there was no difference between males and females. There obviously are some pretty clear ones. Gender is what I was talking about.
If you have a voice that sounds female, and a voice that sounds male... what's the difference? Nothing.
Physiology is something completely different. Sex is completely different. Gender is a made up thing.