Where a child’s parents were never married, most states provide that the child’s biological mother has sole physical custody unless the biological father takes steps to have himself considered for custody. Those steps include obtaining a court’s finding of paternity and filing a petition for custody. In some states, this is a bifurcated (two-step) process; in others, the two steps are combined. An unwed father usually cannot win custody from a mother who is a good parent but he may have priority over other relatives, foster parents, or strangers who want to adopt his child.

See also…

Child Custody and Support

Adoption, guardianships, foster parenting