Maybe the story could focus on how the baby changes their relationship. For example, they might have had some unresolved issues before, but the arrival of the baby forces them to communicate better and work through their problems. And the baby could also inherit some of their skills, like being very observant or having a knack for languages, which could play into future plotlines.
One possible storyline could be that Tony and Ziva decide to raise the baby while still being involved in NCIS cases. They might struggle to balance their dangerous jobs with parenthood, like having to take the baby to the office at times in emergencies. There could also be a lot of cute moments where the NCIS team acts as aunts and uncles to the baby.
Another idea is that there could be a threat to the baby. Since they work in a dangerous field, an enemy from their past could target the baby. This would lead to a high - stakes story where Tony and Ziva have to use all their skills to protect their child while also trying to figure out who is behind the threat.
In this fanfiction, their child might face some unique challenges. Maybe there are people who try to target the child because of who the parents are. Or perhaps the child has to deal with the pressure of living up to the reputations of Tony and Ziva. It could be an interesting story of how the child overcomes these difficulties with the support of their family and the NCIS family.
In some NCIS fanfiction, Ziva could be pregnant. Fanfiction often explores different scenarios for beloved characters. Writers might create a story where Ziva's pregnancy brings new challenges and developments to her relationship with Tony. It could be a plot device to explore deeper emotions and create more complex storylines within the NCIS universe.
There could be many interesting scenarios in such a fanfiction. Maybe they initially struggle to balance their NCIS work with raising a child. For example, they might have to take turns staying home with the baby when a big case comes up. Tony could be the fun - loving dad who plays silly games with the baby, while Kate is the more practical one, making sure the baby has a proper routine.
One possibility could be that it would completely change their dynamic at work. They might become more protective of each other and start to think about their future outside of NCIS. For example, Tony might become more serious and start thinking about settling down in a more permanent way. Ziva, on the other hand, might struggle with how being pregnant would affect her role as an agent.
Another plot idea could be that the child starts to suspect that there is more to Tony and Ziva's past work at NCIS than they've been told. So the child begins to investigate on their own, getting into all sorts of trouble. Tony and Ziva then have to deal with not only protecting their child from external threats but also from the child's own curiosity which could put them in danger.
Another aspect that fanfictions might cover is their future after marriage. Maybe they'll have kids and how they'll balance their family life with their important work in NCIS. It's interesting to see how different authors imagine their married life, from the small domestic moments to the big adventures they might have together.
One plot idea could be that Tony and Ziva are trying to raise their baby while still being involved in NCIS cases. They might have to deal with danger that comes too close to their family. Another could be the baby having some sort of special ability that they need to protect from bad guys who find out about it. Maybe the baby's birth also brings some old enemies of Tony or Ziva back into their lives, creating a whole new set of challenges for them.
If Ziva is pregnant in fanfiction, their relationship could become more intimate. They would have to rely on each other more. Tony might become more protective of Ziva.
The whole team would likely rally around them. They might have a baby shower at the office, with everyone bringing in gifts. Ducky would be excited to have a new little one around and would probably tell stories about when Tony and Ziva were young agents. Palmer would also be helpful, maybe offering to babysit on occasion so that Tony and Ziva can have some time to themselves.
One common theme is the unspoken attraction between them. In many fanfictions, they have feelings for each other but are hesitant to admit it. Another theme is the partnership aspect, how they work together as a great team and that eventually leads to a deeper connection. And of course, the theme of trust, as they learn to trust each other more and more in different storylines.