Let's look at Matthew 13:55-56
"Is not this the carpenter's son?"; why yes this is the carpenter's son, Jesus Christ.
"Is not his mother called Mary?"; why yes Mary is the Mother of Jesus Christ who is God, thus Mary is the Mother of God.
Are you still with me?
Now we have, "and his brethren James, and Joseph, and Simon, and Jude: And his sisters, are they not all with us?" Now James, Joseph, Simon and Jude, all have been identified as brothers of a different mother, or co-workers in the Kingdom of God. So too the sister, perhaps the first "sisters of Clare"
But, you've yet to produce a "soandso", other than Jesus Christ "son of Mary and Joseph"
JoeT