Only one human being has ever lived on the planet Earth.
"Let this mind be in you, which was also in Christ Jesus: who, being in the form of God, thought it not robbery to be equal with God: but made Himself of no reputation, and took upon Him the form of a servant, and was made in the likeness of men: and being found in fashion as a man, He humbled Himself, and became obedient unto death, even the death of the cross" (Philippians 2:5-8).
Humanity is the creation of God. "It is He that hath made us" (Psalm 100:3). We must therefore be what He made us to be in order to fit the definition of "human." By this standard, only the sinless Lord Jesus qualifies to bear the title. Thus He is the only truly human being to have graced the planet, and through Him, God is presently working to produce a vast multitude that bear the likeness of "the man Christ Jesus" (I Timothy 2:5; Romans 8:29).
The fall of Adam distorted humanity. The redemption of Christ redeems and restores humanity to a state that is actually beyond that of our original forefather. We become the literal temple of God when the Holy Spirit indwells us at the time of our new birth, and we also become human according to our Heavenly Father's definition. We begin to love, trust, and obey God in a personal relationship and intimacy that the Lord Jesus perfectly knew in His earthly lifetime, and which we can increasingly know as we grow in His grace and knowledge (II Peter 3:18). Our humanness is actualized, and our unique personality, disposition, history, and Divine reason for our existence begins to be known and expressed.
To be human in God's universe is an amazing wonder. Angels are said by Scripture to be fascinated by the Gospel that began with their Creator becoming a man, and which continues by redeemed men and women becoming authentic men and women (I Peter 1:12). David asked the question, "What is man, that Thou art mindful of Him?" (Psalm 8:4). God answers by pointing to His Son: "That is man." Furthermore, He directs attention to the company of those in whom His Spirit dwells: "That is also man." Yes, the more our hearts and lives reflect the presence of the Divine presence of the Holy Spirit within us, the more truly human we will be. The more also we will glorify our Lord because He "fearfully and wonderfully" made us, and then became as one of us in order to reveal His glory in the most vivid way possible. "God was manifest in the flesh" (I Timothy 3:16).
"And as they thus spake, Jesus Himself stood in the midst of them, and saith unto them, Peace be unto you. But they were terrified and affrighted, and supposed that they had seen a spirit. And He said unto them, Why are ye troubled? And why do thoughts arise in your hearts? Behold My hands and My feet, that it is I Myself: handle Me, and see; for a spirit hath not flesh and bones, as ye see Me have."