This is one of those things the ordinary tourist would simply never even notice: on the facade of Stefansdom one can clearly see — once it's pointed out — these male and female sex organs.  It's the kind of things modern Westerners wouldn't notice because it seems so incongruous to have such worldly symbols on a church.  When Stefansdom was being built you can be sure that the minutest details were scrutinized; this could not have been accidental.