When I started working at a GM dealership it was explained to me that Onstar uses female voices because they are more believeable.
They must never hire Nancy Pelosi or Hillary Clinton then.
Michael Crichton made the assertion in “The Andromeda Strain” that female voices were used in aural warnings because they were more noticable above background noise, even for female listeners.
Just finished a round-trip cross-country 15-state safari visiting relatives and used our Garmin for the first time. It has a fairly well-modulated female voice that we ended up calling "Hilda". If you deviated from the directions, she would harass the crap out of you with repeated "Recalculating - Turn Left on . . . " which was usually the next street as she tried to get you going HER way. After a while we were good-naturedly saying "Shut UP Hilda!".
As for a Homer Simpson voice, I'll pass. Much rather have Apu say "I am not understanding . . .Turn left on . . ."