Wayne has thoroughly explained that Jesus' brothers were indeed his brothers ( of course more precisely : his half-brothers) and not his cousins. All suppositions that it might be otherwise are laboured.
But why does the Roman Catholic church sticks to all this.
Mary must be upgraded at all costs . There must be a construction, that she is always virgin. And the end is, that we have a person, nearly as high as Jesus. And so the attention is drawn away from Jesus, while on him all attention must be fixed, for he is the only Saviour.
And for that purpose, a nearly supernatural Mary, it is absolutely necessary to deny, that she has been a quite normal housewife, bearing children and educating children.
This looks a bit unfriendly, but that is not meant like that. But sometimes things should be said a little sharply.
All earthly forms of Chrisitian beliefs still have their errings. The making of Mary to a sort of 'half goddess' is a specific Catholic erring in my protestant way of thinking.
But never mind Stephan, Psalm 119 v 63 states: "I am a friend to all who fear you, (God) to all who follow your precepts".
And if we both follow Lord Jesus, shouting for joy for our salvation, then we are friends. And all the walls between us will dwindle away.
