Here.

Since the 1970s, 33 states have created Putative Father Registries, designed as a way to link unmarried men to the mother of their child. States expect men to report—voluntarily and honestly—information about all their sexual partners; otherwise, they forfeit their right to be contacted if a partner pursues adoption. The registry is not a petition for custody or a determination of paternity—only a right to notification. Without registry, the wishes of the biological father are irrelevant.