Well, some fanfictions might focus on the relationships that develop as a result of a character becoming a baby daddy. For instance, if Shikamaru were a baby daddy, his laid - back but intelligent nature might influence how he forms a relationship with the mother of his child. It could also be about the challenges he faces in protecting his family in the dangerous Naruto universe, while also teaching his child about strategy and intelligence.
One interesting idea could be exploring how different characters in Naruto would handle the role of being a baby daddy. For example, Naruto himself might bring his positive and determined attitude to fatherhood, teaching his child about perseverance. Another could be Sasuke as a baby daddy, perhaps dealing with his own dark past while trying to raise a child in a more positive environment.