I'm not sure what this "but" is about, but my reasoning goes back to Post #57:
What it means to me is that Mary conceived a son via her egg being fertilized directly by the spirit of God.
which was somehow related to herself having been conceived immaculately. And that is a logical artifice of Romanists ducking the issue of Mary's own seed bearing the essence and stain of original sin, and instead inventing the concept that God fixed it at her own conception by somehow pouring on grace in a way not given to any other descendant of our federal heads, Adam and Eve, to obtain a sinless host from whom Jesus would be formed.
Then your supposition is that somehow the Holy Spirit fertilized Eve's egg (supposedly without original sin?). With what? Eve could at best only supply a haploid cell, and that could never produce masculine characteristics in the child-to-be. So where did the mating haploid cell with the Y chromosome come from? And was it, or was it not formed from a masculine repository of Y chromosomes, some male flesh, somewhere?
And why, if the mechanism of Mary's putative gracious immaculate conception from her father's and mother's seed(s) was real, why did Joseph have to be cut out of the picture? Why could God not have just gracified Mary's egg fertilized by Joseph's sperm to make it a good and sufficient source of a sin-free body receptacle for The Son of God' Spirit to occupy?
Well, this is all about the Romanist philosophers' Aristotlean "rational" solution to this spiritual conundrum at a time in history when they had no knowledge of the biochemistry of meiosis, mitosis, Y and X chromosomes, spermatozoas, oogenesis, recombinant DNA theory, nor of surrogate child-bearing of an baby not of the surrogate's own flesh; and when they simply did not have the humility and grace to just say, "I don't know," and meekly accept the Gospel story as it was presented, trusting in God's Word and not in their own intellectual powers to faithfully retell it.
In your reply I didn't see an answer to the issues I mentioned, and about which you previously asked.
1. You are being too smart by half.
2. Jesus was fully man and fully God.
3. God is omnipotent. He does what he wants and can do anything he wants.
4. If a modern man with strong knowledge of science and biology were to go back in time to the time of Christ or the patriarchs he could be treated as a god. That does not make him god.
5. God supplied the Y. That is why it is called a miracle.
6. I believe every statement above.