Well, one possibility could be that the baby inherits some of Ben's alien powers in a really unique way. Maybe it's not as straightforward as having the Omnitrix, but has some latent abilities that start to show as it grows. And Gwen could be teaching the baby how to control any magical tendencies it might have, since she has her own magic skills.
Well, it could be about how Ben and Gwen adjust to their new roles as parents. Maybe they face challenges like protecting the baby from villains who might want to use the baby's special powers (assuming in the fanfic world the baby has some).
Maybe there are some secret organizations that want to study the baby because it's a hybrid of Ben and Gwen's powers. These organizations might not have evil intentions at first, but their methods of trying to get the baby could make them antagonists as they go against Ben and Gwen's wishes to protect their child.
The baby could have Ben's adventurous spirit. Since Ben is always eager to jump into action and explore new things, the baby might show signs of that same enthusiasm from a very young age. Maybe it would constantly be trying to reach for Ben's Omnitrix - like a shiny object that fascinates it.
In Ben 10 fanfiction, the romance between Ben and Gwen can be really interesting. It often explores their deep bond that goes beyond just being cousins. Writers might develop their relationship in a way that shows how they rely on each other in different situations, like during battles against powerful enemies. They might also show how their feelings for each other grow over time, starting from a simple friendship to something more profound.
One great 'Ben 10 Ben x Gwen Fanfiction' is 'Parallel Bonds'. It explores their relationship in an alternate universe where they have to work together against a new kind of enemy. The story is full of action and also delves into their emotional connection.
A common theme is adventure. Since the original show is about Ben having adventures with his alien forms, fanfictions often continue this trend with Gwen also being involved in exciting escapades.
In the fanfiction, the relationship between Ben and Gwen could change in a complex way. The news of the pregnancy might initially cause some tension and fear between them. But as they gradually accept the situation, they start to grow closer. They might start to see each other in a new light, not just as partners in adventure but as life - long partners in raising a child. This could involve a lot of communication, understanding, and compromise as they navigate through this new chapter of their lives together.
In fanfiction, a story about Gwen being pregnant in the Ben 10 universe could take many directions. It might explore how her pregnancy affects her role as a hero. Maybe she has to take a break from fighting aliens and focus on her well - being and the baby's. This could also lead to new character developments for Ben as he has to step up more in her absence.
I really liked 'Ben and Gwen's Team - Up'. This fanfiction focuses on a mission where Ben and Gwen have to work together in a way they haven't before. It delves deep into their personalities, showing Ben's impulsive side and Gwen's more calculated approach. The story is full of twists and turns, and it keeps you on the edge of your seat. It also has some great character development moments for both of them.