The Physical Nature of Jesus, the Son of God:

Let's take a brief look at how and when Jesus became flesh:

"Paul, a bond-servant of Christ Jesus, called as an apostle, set apart for the gospel of God, which He promised beforehand through His prophets in the holy Scriptures, concerning His Son, who was born of a descendant of David according to the flesh..."  Romans 1:1-3 (NAS)

"And the Word became flesh, and dwelt among us, and we beheld His glory, glory as of the only begotten from the Father, full of grace and truth." John 1:14 (NAS)

"Therefore the Lord Himself will give you a sign: behold, a virgin will be with child and bear a son, and she will call His name Immanuel."  Isaiah 7:14  (prophesying about the birth of Christ - NAS)

"Behold, the virgin shall be with child, and shall bear a Son, and they shall call His name Immanuel," which translated means, "God with us." And Joseph arose from his sleep, and did as the angel of the Lord commanded him, and took her as his wife, and kept her a virgin until she gave birth to a Son; and he called His name Jesus." Matthew 1:23-25 (NAS)

And it came about while He (Jesus) said these things, one of the women in the crowd raised her voice, and said to Him, "Blessed is the womb that bore You, and the breasts at which You nursed."  But He said, "On the contrary, blessed are those who hear the word of God, and observe it." Luke 11:27-28 (NAS)

And when eight days were completed before His circumcision, His name was then called Jesus, the name given by the angel before He was conceived in the womb. Luke 2:21 (NAS)

"And Mary said to the angel, "How can this be, since I am a virgin?" Luke 1:34 (NAS)

Question:

According to the scriptures above, when did Jesus (also called "the Word," "Immanuel," or "the Christ") become flesh?