Is that what you thought I was trying to do? I would really like to know how you get Mary was simply "incidental" to Christ's life out of my mini-lesson on human biology. I have never tried to diminish Mary and have always tried to give her the same honor she was endowed with from Holy Scripture. My point, to repeat, is that Jesus' flesh and blood were unique from Mary in the very same way you are from your own mother. You have her and your father's genetic codes, but you developed from a single cell (ovum) from your mother's body along with your father's sperm cell and they together created an entirely new human being different from either yet linked through common DNA. This in no way means your flesh and blood is your mom's or your dad's.
My further point, in case you missed it, was that Pope Leo XIII wrongly stated something about our Lord and he, in turn, did not say what he did through inspiration of the Holy Spirit, since the HS would know the facts. Do you see that, too?
Everyone's DNA (in every cell) contains enough genetic material from their mother and father to identify their mother and father as their parents in a DNA analysis.