Maybe an angelic or demonic entity implants something in Dean that causes the pregnancy. Dean might initially be in denial and try to hide it from Sam. As the pregnancy progresses, he starts to experience strange powers or sensations. This could lead to a journey where they discover that the unborn entity is a key to saving the world from a great evil.
Well, a plot could involve them trying to keep it a secret at first. They could be worried about how the world around them, especially in their line of work, would respond to two men being pregnant. As the pregnancy progresses, they might start to prepare a nursery together, with each having different ideas about how it should look.
A plot idea could be that Dean discovers he has some sort of inherited power that could be passed on to the baby. This leads to a race against time to figure out if it's a good or bad power. Lisa, on the other hand, is trying to prepare for the baby's arrival in a normal way, like setting up the nursery. Their different focuses create some interesting tension in the fanfiction.
Well, perhaps the baby is a key to closing a major portal to the underworld. Dean discovers this and has to raise the baby while also preparing it for this great task. Along the way, he gets help from Sam and other friends. They face various challenges from demons who want to stop the baby from fulfilling its destiny.
In some fanfictions, Dean might raise angels with a special purpose. Like he raises a group of angels to help him save Sam who has been trapped in a different dimension or something equally dire. The angels have their own motives and secrets, and as they work with Dean, all these secrets start to unfold, leading to a complex and engaging story.
One plot idea could be Abby dealing with the changes in her work life. Maybe she has to adjust her lab work due to her pregnancy. Another could be how the team at NCIS supports her during this time. For example, Gibbs might be extra protective.
One plot idea could be that Dean discovers he's pregnant and is extremely conflicted. He's worried about how John will react, as they have a complex relationship. Maybe at first John is shocked and struggles to accept it, but then realizes he has to be there for Dean. Another idea is that an enemy finds out about Dean's condition and tries to use it against them.
One idea could be exploring how Yennefer deals with the physical and emotional changes during pregnancy while still being a powerful sorceress. Maybe she has to find a way to protect her unborn child from the many enemies she has made.
One idea could be exploring how she and her partner (like Percy) adjust to the news. They might have to deal with the reactions of their friends and family. Another could be the challenges she faces during the pregnancy, like her still wanting to be involved in heroic adventures but having to be more cautious.
One idea could be exploring how Gwen's friends and family react to the news. Some might be overjoyed while others could be worried. Another plot could involve Gwen dealing with the physical and emotional changes during pregnancy while also trying to maintain her normal life, like her hobbies or job. And a third could be about the father's role, if known, and how their relationship evolves during this time.
A plot could revolve around Kushina having premonitions about the future of her unborn child during her pregnancy. She might have dreams that she tries to interpret, and this could add an element of mystery. Also, it could be interesting to see how her pregnancy affects her ninja duties, if she has to take a break or if she finds new ways to contribute while pregnant.