So an Anglican church in New Zealand has managed to stir up a little controversy with a billboard. I laughed very hard when I saw the picture of it in the article I've linked to, but I can still see why the Catholics are so upset about it. After all, they do believe that Mary and Joseph never consummated their marriage; it's been such a deeply-ingrained part of the faith for such a long time that the fact that Joseph was much older than Mary is often played up in Christmas songs and pageants from the Middle Ages—"Joseph was an old man, and an old man was he, /When he wedded Mary in the land of Galilee" and all that. Obviously another denomination's irreverent reference to their belief that she did not remain a virgin after Jesus' birth is deeply offensive to Catholics, and whatever offends the Catholics must surely be offensive to God.
It's a cute joke in a billboard that's obviously doing what it was supposed to do—get people thinking about Biblical things and poke a bit of fun at those who think more about Jesus' birth and death than anything he did in his life. God has a sense of humour; otherwise She/He/It/They would never have caused humans, elephants, chimpanzees or the duck-billed platypus to happen. If your faith is so fragile that a bit of humour threatens it, then perhaps you ought to examine the reason for that. The love of God isn't all "'sorry this' and forgive me that' and 'I am not worthy'"*, after all.
*Credit Monty Python, from "Monty Python and the Holy Grail".