The term natal fathers can be replaced by a variety of synonyms depending on the context or the writer's preference. One synonym could be biological father, which refers to the individual who shares a genetic bond with the child. Another alternate term is birth father, which specifically emphasizes the role of the father at the time of the child's birth. The word sire is also occasionally used as a synonym, though it may be considered more informal. Other possible synonyms could include natural father, genitor, or simply father. It is important to note that regardless of the word used, the father's role in a child's life should always be valued and respected.