FC SD VII.100:  “There is, secondly, the incomprehensible, spiritual mode of presence according to which He (Christ) neither occupies nor vacates space but penetrates every creature, wherever He wills . . . He employed this mode of presence when He left the closed grave and came through locked doors, in the bread and wine in the Lord’s Supper, and, as people believe, when He was BORN OF HIS MOTHER, etc.”

FC SD VIII.24:  “He demonstrated His divine majesty even in His mother’s womb in that He was born of a virgin *without violating her virginity*.  Therefore she is truly the mother of God and yet remained a virgin.”