indicate if a contact is male or female

Just a little question: What exactly are the "universal" male and female symbols? Mars ♂/ Venus ♀ symbols ? Or man in trousers 🚹/ woman in skirt 🚺 ?

I think we should make it clear for all people around the world that may use elementaryOS.

My guess is that universal symbols refers to ♂ and ♀. However in the real world they are quite rare. I see them so rarely that I actually can't remember which is which. On toilets, changing rooms and the like you usually see various versions of “man” and “woman”, either as picture, pictogram or written out - if you were to put a ♂ on the toilet there's a 50:50 chance of an embarassing situation. I'm speaking for countries in Europe here, it may be different elsewhere. Let's keep the infamous Gtk.Switch in mind which demonstrated what happens when you mistake local customs for universal rules.