It seems as if my answer on this post would also answer your question here.
Is Mary's virginity evidence that sex is always sinful?Is Mary's virginity evidence that sex is always sinful?
I believe that Mary's virgin Birth was a testification to the Truth of Christ. Could you imagine what the Catholic church would have done with the Husband? "Father of God" I'm sure that would have been completely chaotic. Who's really the father of God?
Well, we know through the virgin birth that only God the Father is the Father of Jesus Christ.