An observation on Christ and the Church: The Christmas Mass has a nice reading from Isaiah on the arrival of Emmanuel, born of a virgin. Rabbi Zimmerman remarked with a 'don't let this get out' kind of expression once that the Catholics had mistranslated the word they were taking for 'virgin.' In Hebrew it may mean just 'young woman.'
Catholicism has high standards for marriage and sexual relations. In 1st Corinthians, Paul answering the question what it takes to be Christian starts out with a 'proper marriage.' If your spouse leaves, you're stuck with having to get an annulment. I wonder if the severity doesn't really start with Mary (or center on her).
An, in a sense, competing line of justification for the Kingship of Jesus falls on his being a descendant of David. This is competing in my view because, if the Holy Spirt was the father and not Joseph, then where's the line of descent?