Christ is one Person, two natures, in perfect harmony, fully divine and fully humam, inseparably fused, but not confused.
My understanding is that God the Word took on human nature, using Mary's flesh in her womb, which He entered mystically without violating her.
The Church always taught that His mystical Birth likewise did not violate her.
He was not a pagan byproduct of some divine-human sexual union, a demigod like Achilles, a mixture of divine and human "seed."
Incarnation is an act of the Word of God, His will, and not a "natural" consequence.
I find it hard to accept that someone who's not remotely connected to human experience can be said to be "fully human."