If parents are married when a child is born California law assumes that the husband is the father and the wife is the mother. When a child is born and the parents are unmarried, the parentage of the child needs to be legally established. A Declaration of Paternity is one of the ways to do this. The Declaration of Paternity says who the legal parents of the child are. Hospitals are required to provide to any unwed mother and attempt to provide to the man identified by the mother as the biological father a voluntary Declaration of Paternity.