In as much as Christ assumed our nature completely, and in the fullness of time, we have come to understand that our nature includes carrying within our bodies instructions, encoded in DNA, for our physical makeup, plainly Christ's body, like unto ours, did so as well.
It seems fruitless to speculate how the action of the Holy Spirit accomplished the wonder not merely of a virgin giving birth, but a virgin giving birth to a son. Doubtless one of the wonders in the life to come will be having such matters cleared up to our amazement at God's cleverness in addition to His condescension.
A blessed and merry Christmas to all!
Adam and Eve did not have that and they were fully human.
Incarnation is a mystery, not ordinary conception. There is nothing that necessitates or justifies any speculation as regards to that miracle. Least of all claiming that Mary's egg was somehow "fertilized." Fertilized ovum is a separate individual. C hrist was one and the same Divine Person, Logos, before and after.