That's only a little bit of common sense and biochemistry. I'm afraid you've given your argument too many free passes to be able to continue with it. Personally, I don't believe any part of Mary's Adam-derived biology is that from which Jesus' perfectly sinless fully human body was formed.
As I said before that He said (fully applying Psalm 40:6), "Sacrifice and offering thou wouldest not, but a body hast thou prepared (καταρτίζω katartidzo) me (dative case):" (Heb. 10:5c,d AV; my parenthetical insertions).
κατηρτισω = verb; aorist tense, middle deponent voice, indicative mode; second person singular.
To me, the sense of the verb imparts the notion that the body was made sometime in the past prior to the moment the living zygote attached to Mary's womb. It is not too much of a stretch to think that the Personality of The Son was invested into an incredibly complex carnal frame, though one-celled, that He might experience all that a human would expect to endure, including living in a natrous fluid climate without breathing for many months:
"For we have not an high priest which cannot be touched with the feeling of our infirmities; but was in all points tempted like as we are, yet without sin" (Heb. 4:15 AV).
And to press this home, it could be that he was clothed in exactly the same flesh as Adam's spirit was, with exactly the same body and brain chemistry as Adam, thus obviating any excuse for genetic differences; and faced with exactly the same choices: to be obedient, or to be disobedient, that was the question.
I believe that His humanity had to be experienced (like learning to ride a bike) and obedience had to be exhibited at least to onlookers by playing it out, as suggested to us:
"Though he were a Son, yet learned he obedience by the things which he suffered;
And being made perfect, he became the author of eternal salvation unto all them that obey him;" (Heb. 5:8-9 AV).
Please also note that Jesus is never referred to as a son begotten by Mary, as of necessity were her other children.
"God hath fulfilled the same unto us their children, in that he hath raised up Jesus again; as it is also written in the second psalm, Thou art my Son, this day have I begotten thee" (Acts 13:33; cf Ps. 2:7, Heb. 5:5)(He was the first-begotten from the dead ones).
Remember, the begetting and the time of birth are quite spaced in time, so though Jesus was Mary's firstborn son (Mt. 1:25, Lk. 2:7), it is possible that she might not be any part of the begetting (that is the joining of the components of the single-celled zygote), she was the conceiver (that is, the person to whose womb wall the zygote attached, and was sustained and nurtured).
In the Bible, The Father said, "I (and it may be taken to mean only I) have begotten Thee." Not "We have begotten Thee." That would kind of exclude Mary as contributing to the carnal component of Jesus, but certainly contributing to the experiences that integrated Him into humanity. Eh?
I think it was the Father that prepared His body, not The Father plus Mary, which would have made it plural.
Strong's Number G2675
Strong's Definition:
καταρτίζω
katartizoh
kat-ar-tid'-zo
From G2596 and a derivative of G739; to complete thoroughly, that is, repair (literally or figuratively) or adjust: - fit, frame, mend, (make) perfect (-ly join together), prepare, restore.
Thayer Definition:
1) to render, i.e. to fit, sound, complete
. 1a) to mend (what has been broken or rent), to repair
. . 1a1) to complete
. 1b) to fit out, equip, put in order, arrange, adjust
. . 1b1) to fit or frame for one’s self, prepare
. 1c) ethically: to strengthen, perfect, complete, make one what he ought to be
Part of Speech: verb
The Father did prepare/fully fit out/thoroughly complete a body for Him. It did not necessarily have to be any of Mary's cellular material, and could be with a quite reasonable pattern like the body of the first Adam was formed prior to receiving the quickening spirit to become a complete human, so also the body fitted out for the Last Adam in The Father's marvelous (and sinless) biochemistry lab.
Perhaps the body was actually of the exact same identical cellular construction that Adam's was; for when it was first formed, Adam's DNA was meant to live forever, and was corrupted only by Adam's disobedience.
The same un-sin-stained holy male flesh as a single-celled zygote might have been implanted into Mary's womb, similar to the medical methods now in general use, like as we implant a surrogate mother.
The God The Father could do that with the same ease with which you say that His Only Begotten-in-the-flesh Son's Body got the Y chromosome, but you haven't provided a way to twiddle Mary's flesh in an unnatural or supernatural way as your suggestion implies.
The hypothesis presented here has much less difficulty both temporal and eternal than the contrivance cobbled together by the Romanists, and dogmatized in 1854 ex cathedra in a state of biological ignorance not consistent with now-known facts.
"Too smart by half" is not adequate to justify your own conclusions, my FRiend, IMHO.
I still think you are over-thinking it. But opinions vary.