That is an interesting comment, for it was my impression that the flesh and blood of Christ was not His but Mary's. Else, whence came His own flesh? If He were to be indeed covered by pre-fall flesh, then it would make sense what the Latins believe -- Mary would have to be the pre-Fall Second Eve or else her own flesh would be a post-Fall flesh.
But I will take this a step farther: first Adam did not have a mother. Why would the second Adam need one? So that He could be from the line of David? But I thought the lineage in Judaism was passed via the male line, so how could Christ claim Davidian lineage through His Mother?
Besides, Christ could not have been genetically the same as we are. His humanity comes from His Mother alone. Not exactly like the first Adam, is it?
I don't have very good answers for your questions. I am perhaps being imprecise in my recollection of exactly what terminology is used by Metropolitan Hierotheos (Vlachos) in his writings on the teachings of St. Gregory Palamas regarding theosis and the Theotokos.
The liturgical texts say that Christ "took flesh of the Virgin." But on the other hand, once he was conceived, he was a unique person, so it only makes sense to say that his body contains his own flesh and blood. The emphasis of St. Gregory Palamas is on the intimate association of Christ's body and blood with that of the Theotokos during his 9th months in her womb, as I recall. Again, my recollection and wording may be imprecise.
I hadn't really thought about the question of why Christ "needed" a mother. I suppose that I always thought that God expected mankind to work its way back to him. This began outside the gates of Eden, where Eve is told that her seed would bruise the serpent's head. Also, while it isn't often talked about as such, the entire human race shares a common nature. We are all linked physically to each other through our common ancestry in Adam and Eve. For Christ to fully share our nature, he would need to be physically linked with us in that common ancestry.
Part of the emphasis in the two lineages given in the Gospels of Matthew and Luke is the role of adoption. Christ was the son of Joseph by human adoption, and likewise Joseph himself was of a kingly line (St. Matthew's lineage) through adoption (several fathers give this explanation.)
The lineage in Luke is also a geneology leading to Joseph, again showing that he was of the seed of David, but it is a strict blood-line, with no adoption involved (adoption being in the form of a man "raising up seed" to his brother dies without an heir. The fathers explain that the two lineages show that whether one "counts" these "raising up of seed" for a brother or not, Christ is descended from David. And in either case, at the final point in the lineage, Christ's lineage is always traced to his adoptive father, Joseph, in the Gospels. It is a male lineage.
This is appropriate, since we are children of God by adoption -- not by nature or essence.
There is no geneology anywhere in Scripture of the Theotokos herself. It is my understanding that she was of the tribe of Levi (thus her cousin Elizabeth being married to a high priest.) Others, based on the fact that Joseph was an elderly distant relative of hers, believe that hers was either also of the tribe of Judah and general lineage of David, or that her family was of both tribes.
This would be not at all unlikely, since the "lost" ten tribes of Israel included the tribe of Levi. The Jewish nation at the time of Christ was primarily of the tribe of Judah, but doubtless had remnants of all of the other tribes absorbed into it. Some traditions have claimed that the 12 apostles came from lineages of the 12 tribes.
Either way, in Christ, we have the union of the priestly and kingly lineages within the nation of Israel.
I'm not sure about your questions about Christ's genetic likeness to us. Are you raising the question of whether he was haploid or something? :-)