Matthew tells us that when "Mary had been betrothed to Joseph, before they came together she was found to be with child of the Holy Spirit; and her husband Joseph, being a just man and unwilling to put her to shame, resolved to divorce her quietly."
Why did Joseph intend to divorce Mary?
The view that suggests itself to most people is that Joseph thought Mary had been unfaithful to him.
But there is another theory: that Joseph knew the Child had been conceived "of the Holy Spirit" and so Joseph was afraid to take Mary as his wife.
What are we to make of this issue?
And what does Pope Benedict have to say in his new book, Jesus of Nazareth: The Infancy Narratives?