Complex sentence: A Putative Father Registry is a state level legal requirement for all non-married males to document through a notary public with the state each female they engage in heterosexual sexual intercourse with in order to retain parental rights to any child they may father.
Split into simpler sentences: A Putative Father Registry is a state level legal option for unmarried males to document through a notary public any female with whom they engage in intercourse. The purpose is for the male to retain parental rights to any child they may father.