The biggest source of confusion may turn out to have been my typo. I meant to say, relying on the unity of two natures in one person, secundum Chalcedon, that when Mary hearD the heartbeat of her child, she heard the heartbeat of God.
Again, I think that daniel1212's proposition that the expression "Mother of God," implies ontological unity is mistaken. The suggestion that "Mother of God" has the same sort of implication as "Son of God," is very unlikely to be true.
Paul, IIRC, makes a distinction between "children" and "sons" because, as he says, "If sons, then heirs." The mother of the child is mother in any case, but the Father must acknowledge the child.
(This is why some 'de-sexing' and politically correct translations run the risk of blurring important matters.)
Further, as I have already written, in the biology of the time (and up to at least the time of Aquinas), the mother only supplies the 'stuff,' of the child while the quiddity is supplied by the Father.
Now, the hairy parts:
First, there is no denying that, leaving aside those formally charged with heresy, there is a lot of Marian nonsense out there. There are times when I want to give Crazy Louie and others a good shake! And this issue is complex, IMHO.
For example, in both the Memorare and the Salve Regina there is language that is over the top theologically. I personally found the Salve repellent until I heard it sung in Latin by some Cistercians after night prayers. Then I 'got' it.
And what I 'got' was something of which many non-Catholics do not think, and upon which they look with grave misgivings: Marian devotions (and devotions to other saints) often lead to deep affection. And the language of affection is not philosophical or theological. I make predications of my daughter TO my daughter that she and I both know are not, strictly speaking, true. But I am not going to stop saying she's the most wonderful girl in the world.
Words suggesting Necessity
When we say things like,"God HAD to to thus and such to redeem the world," it's a little more complicated that it may appear. As far as we know, God could have made what seemed to be a neonate (who was also God) without the involvement of a woman at all. Or He could have just presented to the world a perfectly human thirty-year-old Jewish guy (who was also God). This is one of the reasons that I prefer the word "fitting" to "necessary." We 'know' what He DID. He wouldn't do anything indecent. Therefore ...
okay That's quite enough for one post. Let me catch my breath and I will drone on (and on... and on .... and zzzzzzzz).
I am told that in both the original and the remake of Sagan's "Cosmos" there is a hint that in thinking that among all these billions and billions of stars, man would be the only rational animals is ego-centric. But a fortnight ago I urged my, ahem, auditors to consider that maybe, just maybe, God is 'crazy in Love with us.' Maybe we should look at all these splendors and wonders as something like the extravagant expressions of love which adolescent boys used to liable to.
In other words, what the atheists think is ego-centrism or vanity is not something we think about ourselves, but something we think about the ever-astonishing generosity, extravagance, one might even say profligacy of God.
Okay. Mutatis mutandis, despite the clear language of Ineffabilis Deus
... beatissimam Virginem Mariam in primo instanti suae Conceptionis fuisse singulari omnipotentis Dei gratia et privilegio, intuitu meritorum Christi Iesu Salvatoris humani generis, ab omni originalis culpae labe praeservatam immunem, ...people strangely persist in saying that there was something other than (to be redundant) gratuitous grace involved -- grace flowing through the saving act of IHS -- in Mary's immaculate conception. I can understand how one might disagree with the dogma. I cannot understand how anyone could say that WE TEACH that this had to do with intrinsic merits or characteristics of our Lady. Just as her being Theotokos, Dei Genetrix, and Dei Para depends not on her but on the gift and "operation" of the Holy Ghost, so also the only source of her freedom from sin is God Himself and His act in IHS XP.... the most Blessed Virgin Mary, in the first instance of her conception, by a singular grace and privilege granted by Almighty God, in view of the merits of Jesus Christ, the Savior of the human race, was preserved free from all stain of original sin, ...
Another reason to consider this dogma is to think about God and Time. In the union of the two natures in One Christ there are interesting aspects concerning time and eternity:
Before time began he was begotten of the Father, in respect of his deity,The relationship of time and eternity leads to interesting problems of theological expression. As an example, the Sin of Adam is from Creation to Easter, an utter disaster. But from Easter to the Consummation it is the "felix culpa," the happy fault which led to so astoundingly great a redemption:
and now in these "last days," for us and behalf of our salvation, this selfsame one was born of Mary the virgin, who is God-bearer, in respect of his humanness.
O certe necessárium Adæ peccátum, quod Christi morte delétum est!
O felix culpa, quæ talem ac tantum méruit habére Redemptórem!
(I think I should say that I have been copared to jukebox. Put in a question, and I blab for half an hour.
But this is enough for one post.)