Their relationship could become stronger. With a son, they have a new bond that ties them together even more. They might communicate more often and share their parenting experiences. They could also rely on each other more in terms of protecting their family.
Some in the ninja world would likely be shocked at first. The idea of Naruto and Sasuke having a son together goes against the traditional views of many. But those who are close to them, like their friends from Team 7, would probably be supportive. Kakashi, for example, might see it as a new step in the evolution of the ninja world's relationships. However, there would also be those who oppose it, especially from more conservative clans who might fear the implications of such an unorthodox union on their power structures.
Well, one possibility is that the story could focus on how they raise their son. Maybe their son has some special powers inherited from Sasuke and Sakura, and they have to train him to control it. Another idea could be that the son gets into some kind of trouble in the ninja world, and Sasuke and Sakura have to work together to protect him. There could also be some family drama, like the son having a conflict with Sasuke because he doesn't understand his father's past actions.
One possible plot could be that Naruto and Sasuke's son becomes a bridge between the two villages. Since Naruto is from Konoha and Sasuke has his own complex history with Konoha as well as other places. Their son might inherit Naruto's positive attitude and Sasuke's strong will. He could grow up with unique powers, a combination of Naruto's Uzumaki and Sage of Six Paths powers and Sasuke's Sharingan and Rinnegan. And he might be on a journey to further strengthen the bond between Konoha and other villages, facing challenges along the way that test his abilities and his understanding of his two fathers' legacies.
If Sasuke's sister was in the picture, Naruto and Sasuke's relationship might soften more quickly. Naruto would see another side of Sasuke through his sister. He might also feel more of a connection to Sasuke's family. Sasuke, on the other hand, would see Naruto's genuine care for his sister, which could make him trust Naruto more.
In these fanfics, one characteristic is the growth of their relationship. At first, Sasuke may be aloof, but gradually he opens up to Sakura. Sakura, on the other hand, is always steadfast in her love. Another is the mutual support. They often face difficulties together, be it in battles or in rebuilding their world, and they rely on each other's strength. Also, there's the element of deep understanding. They come to understand each other's past traumas and insecurities, which brings them closer.
He might focus on rebuilding relationships. After the war, Sasuke could be trying to mend his bonds with Naruto and the others in the fanfiction. He may also be involved in restoring his clan's honor in a more peaceful way.
Naruto might protect Sasuke by using his physical strength. He's got those powerful jutsus like the Rasengan. If any enemy comes near Sasuke, Naruto can just blast them away with his attacks.
His understanding of relationships might grow. Through his interactions with Sakura, Sasuke could learn about compromise, forgiveness, and unconditional love. For example, he might learn to forgive himself for his past mistakes and understand that Sakura loves him despite all that.
In these fanfictions, Sasuke often becomes more responsible. He was once a brooding and solitary ninja, but as a baby daddy, he has to think about someone other than himself. For example, he might start to plan for the baby's future, which is a big change from his usually self - centered ways.