What would you call a biological father who is not yet been legally established as the child's father by a court?

The term "Putative Father" is referred to the biological father who is not yet been legally established as the child's father by a court. A "putative father" is a term used in many states to describe a man who is either alleged to be the father or claims to be the biological father but who is not married to the mother at the time of the child's birth.