But as many as received Him, to them He gave the right to become children of God, to those who believe in His name, who were born, not of blood, nor of the will of the flesh, nor of the will of man, but of God, John 1.12-13.

First – Children born of blood – are children born by chance;
Second – Children born of the will of the flesh – are children born because a man and a woman had consensual sex;
Third – Children born of the will of man – are children that are born because their parents planned to have them;
Fourth – Children born of God – are children, youth and adults born of the Holy Spirit.
From a biblical point of view, the first three children are classified as those born of the flesh, John 3.6.
Only those who are born of water and the Holy Spirit, like Jesus, are children of God, John 3.5.

In general, the process of being born again, this is, being born of water and the Spirit (John 3.5), require the following two steps:

a) born of water – is the death of sinful desires and the burial of the sinful body through the baptism in water;
b) born of the Holy Spirit – After the first step, which is repentance, comes the descent of the Holy Spirit, which represents Jesus.

Now if anyone does not have the Spirit of Christ, he is not His, Romans 8.9.