In Illinois, a putative father is a man who believes that he has fathered a child but who was not married to the child's mother when it was born. To preserve his parental rights in this situation, a man who believes that he is the legal father of a child must first register with the Illinois Putative Father Registry. This must be done within 30 days of the child's birth and may be done prior to the child being born.
In addition to registering, a father must also begin legal proceedings to establish paternity within 30 days of the child's birth. This may be done by signing a Voluntary Acknowledgement of Paternity form or by asking a judge to make a ruling. Assistance in taking such action may be available for free under certain circumstances.