These investigations had varying degrees of complexity. Today, virtually every state requires some form of investigation into the suitability or fitness of the individuals seeking to adopt. The investigation usually involves a report referred to as a home study. Generally, home studies are conducted prior to the placement of the child with a family. Sometimes it is following the placement of a child with a family but prior to the finalization of the adoption.
Consent is the most common method to achieve a voluntary termination of parental rights.
Biological but unwed fathers had no recognized rule until the 1970's. In many states, biological unwed fathers still do not have a presumptive right to consent or veto an adoption, but merely a constitutional right to notice and an opportunity to be heard. Involuntary Termination of Parental Rights Statutes detailing the ground upon which parental rights may be involuntarily terminated commenced in the 1970's. The due process clause of the United States Constitution requires that severance of a parent's rights be supported by clear and convincing evidence. Generally, state statutes view involuntary termination of parental rights as an action of last resort.