Luke 1:35 "And the angel answered and said unto her, The Holy Ghost shall come upon thee, and the power of the Highest shall overshadow thee: therefore also that holy thing, (thing, here means flesh), which shall be born of thee shall be called the Son of God". notice shall be called, not named, but called Son of God, (flesh is born), Son of God means flesh on earth. go back to Isaiah. 9:6, "unto us a child is born". so Son of God means, flesh in nature, a nature that will suffer the cross.This post is irrelevant to His conception.
note also the word overshadow, it's the Greek word G1982 ἐπισκιάζω episkiazo (ep-ee-skee-ad'-zo) v.
1. to cast a shade upon
2. (by analogy) to envelop in a haze of brilliancy
3. (figuratively) to invest with preternatural influence
take note of the 3rd. reference. "to invest with preternatural influence", what do preternatural means. It means, "out of the ordinary course of nature; exceptional or abnormal". the meaning here, not in the natural way of conception between a man and a women. this body as I have said, God conceived or God made, and “formed” in Mary’s womb. Did he not formed Jeremiah body in his mothers womb before he was born, or brought forth. for the scripture states, "prepare me a body"', Hebrews 10:5. now notice it said prepare, not create a body. because God always existed, and by making or preparing a body as he did Adam's with preexisting material, earth. God, with his preexistence, the first law of thermodynamic is not violated, and as he did with the heaven, as well with the earth, he can make, prepare anything he wants, by simply speaking it into existent, (and God said let there be ....). so that body/flesh was prepared/made from the invisible, (as with all visible things) made he it visible, by generating it in Mary's womb.