Today Is...World Voice Day

I have spent a lot of time with my Sat Nav this past week and the lovely, soothing female voice telling me to take the next exit and then perform a U-turn at which point i would turn to my phone and Siri who again in a pleasant female tone would tell me she couldn't answer my question.
Although there is an option for a male voice to take you the wrong way on the motorway, the default voice for many artificial intelligence systems does seem to be female and after watching a programme about robots, it seems that most of the humanoid robots are also.
I have asked why the female form and voice are used in these types of things and the answer is that females are less threatening and sound more soothing for the users then males and women’s voices are just easier to understand.
In English, women tend to enunciate vowels more clearly and speak at a higher, more distinguishable pitch which all makes sense as i admit i call on them for everything from measuring how long my journey to work will take if i leave at a certain time, to asking when the rain's going to end and who sang that half
forgotten 80's song which has been bouncing around inside my head all day but i am sticking with my original thought that if it is intelligence, and male, it follows that it must be artificial so they use female voices instead.