Christ is fully human and fully God, the difference is the Christ as God did not have all of His glory and became flesh
Psalm 51:5 (KJV) Behold, I was shapen in iniquity, and in sin did my mother conceive me.
That is in reference to everyone born into this world and not Jesus Christ... Sin is always passed down from the male not the female... Mary was just the vessel to birth the eternal holy seed... Jesus Christ in his flesh had no sin as his Father is God... So he bore our sins and his too on the cross?... You are new here but understand this... Jesus Christ was born in this world sinless and he left the same way... When you take scripture out of context error happens... This scripture applies to David who said it, him and us only NEVER to Jesus Christ... Seeking Christ... You'll learn... Brother Glen