Child custody in case of live in relationship

Need inputs in the Case: Child Custody/Visitation rights/laws in case of Live-In Relationships.Partners cohabitat as Husband and wife but did not register the relationship.A son, now 6 yrs old, was born out of the Rship. The woman has gone back to reside with her parents and has taken taken away the kid and not allowing father right to access. Woman is demanding money for the same.The Birth certificate doesnot mention the name of father. However in school records the name of father is mentioned.