I may have two views on this brief and remain open for corrections;
First view:
In presented briefs the biological father claiming custody of 'ilegitimate child' will loose case and natural mother will get final legal custody of child as the Law in Guardianships proceedings also says that the mother is the guardian of the minor "illegitimate child" which is most important wordings wise even if the biological father is alive. Further the mother’s right to guardianship stays even if she has converted her religion. Still further, the position also remains the same even if the child is an adopted child and not a natural born child.
Re.: Giita Hariharan v. R.B.I. JT 1999 (1) sc 524
Re.: Vandana Shiva v. Jayanta Bandopadhyay AIR 199 SC 1149
Reasoning:
Here the main cause is that of claims by a biological father claiming custody who is not a 'natural guardian' as per HAMA S. 6. First hurdle he has is to clear and establish he is 'natural guardian' of the child. Since the child is below S. 6 HAMA age he has this disadvantage as in plaint mentioning. Now, secondly I see that since there was no legal marriage between them he is in again in disadvantageous position to establish that there was a legal marriage and it is in ‘welfare of the child’ that custody be given to him. Thirdly in the absence of divorce decree by his married live-in i.e. the mother of the illegitimate child the natural mother can't claim this biological father to be her husband even by way of her W/s. Forth the child in such circumstances will be given in custody to mother.