Two blue lines

St Matthew's church in Auckland, New Zealand, has a habit of putting offensive posters outside their church for Advent. This years one has been more controversial than usual and have invoked much anger, including vandalism.

Personally, I have no problem with it. Even though it was in faith Mary accepted her call to bear God's son, I suspect the reality of that would still have come at a surprise. What to tell Joseph and her parents? What would the community think? Will she survive pregnancy and childbirth?