The Holy Tradition never, ever taught that Christ jumped out of Mary head or any such nonsense. The only misunderstanding comes from (obviously deliberate) distortion and caricature of what the Church clear believed and taught all along.
How then are these teachings supported in the RCC?
Ignatius is probably the earliest to deal with the virgin birth outside of scripture, and especially since he is a disciple of the Apostle John, one would think his understanding worthy of note. So close was he to the 1st era of the church (lived from about the 60's AD to about 120 AD) that spurious letters between Ignatius and Mary appeared. He was martyred in Rome. See Chapter 10 of Letter to Trallians
But if, as some that are without God, that is, the unbelieving, say, He became man in appearance [only], that He did not in reality take unto Him a body, that He died in appearance [merely], and did not in very deed suffer, then for what reason am I now in bonds, and long to be exposed to72 the wild beasts? In such a case, I die in vain, and am guilty of falsehood73 against the cross of the Lord. Then also does the prophet in vain declare, "They shall look on Him whom they have pierced, and mourn over themselves as over one beloved."74 These men, therefore, are not less unbelievers than were those that crucified Him. But as for me, I do not place my hopes in one who died for me in appearance, but in reality. For that which is false is quite abhorrent to the truth. Mary then did truly conceive a body which had God inhabiting it. And God the Word was truly born of the Virgin, having clothed Himself with a body of like passions with our own. He who forms all men in the womb, was Himself really in the womb, and made for Himself a body of the seed of the Virgin, but without any intercourse of man. He was carried in the womb, even as we are, for the usual period of time; and was really born, as we also are; and was in reality nourished with milk, and partook of common meat and drink, even as we do. And when He had lived among men for thirty years, He was baptized by John, really and not in appearance; and when He had preached the Gospel three years, and done signs and wonders, He who was Himself the Judge was judged by the Jews, falsely so called, and by Pilate the governor; was scourged, was smitten on the cheek, was spit upon; He wore a crown of thorns and a purple robe; He was condemned: He was crucified in reality, and not in appearance, not in imagination, not in deceit. He really died, and was buried, and rose from the dead, even as He prayed in a certain place, saying, "But do Thou, O Lord, raise me up again, and I shall recompense them."75 And the Father, who always hears Him,76 answered and said, "Arise, O God, and judge the earth; for Thou shall receive all the heathen for Thine inheritance."77 The Father, therefore, who raised Him up, will also raise us up through Him, apart from whom no one will attain to true life. For says He, "I am the life; he that believeth in me, even though he die, shall live: and every one that liveth and believeth in me, even though he die, shall live for ever."78 Do ye therefore flee from these ungodly heresies; for they are the inventions of the devil, that serpent who was the author of evil, and who by means of the woman deceived Adam, the father of our race.