Atheist confused concerning the necessity of the virgin birth of Messiah-Jesus. An explanation…
The first prophecy concerning Messiah’s birth via the seed of the woman is Genesis 3:14-15. Messiah’s virgin birth was a necessity due to Adam’s culpability for the Curse resulting in a corrupted genome, a sin-nature, death of the body and spiritual death…a chasm created between mankind and God due to rebellion and disobedience.
So the Lord God said to the serpent:
“Because you have done this,
You are cursed more than all cattle,
And more than every beast of the field;
On your belly you shall go,
And you shall eat dust
All the days of your life.
15 And I will put enmity
Between you and the woman,
And between your seed and her Seed;
He shall bruise your head,
And you shall bruise His heel.” Genesis 3:14-15 (NKJV)
If you remember, when Eve succumbed to the enticement of Lucifer in Eden, nothing happened. Elohim took no affirmative action concerning judgment or wrath. Not until Adam compromised with Eve and rejected God Covenant of Provision that hinged upon not compromising with evil did Elohim search-out Adam and subsequently pronounce The Curse for disobedience (Genesis 3:17-19).
It is Adam that bears the greater culpability for The Fall seeing that Adam received the edict from Elohim to NOT compromise with evil DIRECTLY from the mouth of God. Eve, on the other hand, received the edict by hearsay from her husband; therefore, death, the curse, the chasm, is passed from the seed of the man.
Jesus entered Time through the womb of the woman (Galatians 4:4) in order to circumvent the sin-nature, the corruption, that passes from our first father, Adam (Romans 5:12; 1 Corinthians 15:22). Jesus was born in the flesh fully man and fully God (Philippians 2:8) and this Plan, the Gospel, finds its origin “before the beginning of Time” (2 Timothy 1:10; 1 Peter 1:20).
Jesus was born into the World, born to a “woman,” born under The Law (Galatians 4:4) and Jesus lived a perfect sinless life and fulfilled The Law for us (Matthew 5:17-20) as Jesus was the only One capable of fulfilling the law and meeting the righteous standards of perfection required by God the Father (2 Corinthians 5:21); otherwise, Jesus could not have died as the propitiation/sin-bearer for the sins of mankind (John 3:16).
If Jesus was not born of a virgin, He could not be God because He would be tainted with a sin-nature and Jesus would not have been able to fulfill the righteous requirements of the Law and we would all be dead in our sin and headed to a hopeless death in Hell subsequent to Judgment (Romans 5:8).