Son of God

When you are born naturally, you become your parents' son or daughter. When you are born by the Spirit of God, it's only then you become a son or daughter of God. 'As many that receive Him, to them He gave power to become sons of God.'

Some say we are all sons of God which is not true. In fact, we are all God's creation but not all His sons. 
For if ye live after the flesh, ye shall die: but if ye through the Spirit do mortify the deeds of the body, ye shall live. For as many as are led by the Spirit of God, they are the sons of God. (Romans 8:13, 14 KJV)

'Every tree shall produce according to it's kind.' Notice that in the Bible trees type human beings. That is why you behave like your parents because you were born by them. But when you are born by the Spirit of God, His Spirit comes to dwell in you and you act and behave like God. It is therefore imperative that everyone is BORN AGAIN so we can have the Spirit of God which is immortal and only then we can claim that we are sons and daughters of God and that we have eternal life. If you are born by flesh, the works of the flesh you will produce. 

All have sinned and have come short of the glory of God. (Romans 3:23) Jesus was born by the Spirit of God and that's why he did not need to be born again because that made Him sinless.

Now the birth of Jesus Christ was on this wise: When as his mother Mary was espoused to Joseph, before they came together, she was found with child of the Holy Ghost. (Matthew 1:18 KJV)

This is why Jesus was called the Son of God. He is not a third person in the Trinity, He is Emmanuel, The Almighty God with us. If you are not sure of this, read Isaiah 9:6 again and this time, carefully.

For unto us a child is born, unto us a son is given: and the government shall be upon his shoulder: and his name shall be called Wonderful, Counsellor, The mighty God, The everlasting Father, The Prince of Peace. (Isaiah 9:6 KJV)

On the Mount of transfiguration God spoke and said 'this is my beloved Son, hear ye Him.' If you can only listen to Him, saying 'you must be born again,' eternal life awaits you.