A theme that can't be ignored is the role of Torchwood in this situation. Will they protect Ianto? Will they try to find out the cause of the pregnancy? How does the organization's mission and secrecy play into this? Fanfictions might show Torchwood using their resources to deal with this unique case, or they might struggle to keep it under wraps while also dealing with the internal and external implications of Ianto's pregnancy.
Relationships are also a big theme. As I mentioned before, how his relationship with Jack changes is often explored. But also, his relationships with the other Torchwood members. They might be supportive, or there could be some jealousy or confusion among them. And of course, there's the theme of the pregnancy itself - the physical and emotional changes he goes through, like morning sickness, mood swings, and the anticipation of becoming a parent.
There are some great Torchwood fanfictions out there with this unique concept. One place to start looking could be Archive of Our Own (AO3). It has a large collection of Torchwood fanfics, and you can search specifically for ones where Ianto is pregnant. You might find some that explore the emotional and physical aspects of his situation in really interesting ways.
One common theme is the impact on relationships. Her relationship with Rhys becomes even more central as they prepare for parenthood. Another theme is how her pregnancy affects her work at Torchwood. There's often a struggle to balance her duties there with her new - found maternal responsibilities. Also, there can be themes related to the potential of the unborn child having some sort of special ability or connection due to all the alien exposure in Torchwood.
One common theme is survival. Given Owen's often - precarious situations in the show, many fanfictions explore how he manages to survive against all odds. For example, in some stories, he has to deal with life - threatening alien encounters alone.
One common theme is the clash of different kinds of supernatural or otherworldly elements. Since 'Supernatural' has a lot of demons, angels, and ghosts, and 'Torchwood' deals with aliens and time - space anomalies, when they cross over, there's often a struggle to understand and combat these different threats. For example, in many fanfics, the characters have to figure out how to fight an alien - possessed demon or something similar.
A common theme is his upbringing. It could be about his family values, how he was taught certain things as a child. Another theme might be his first adventures or experiences that set the stage for his future. For example, his first encounter with something mysterious in his hometown as a child.
One common theme is the exploration of forbidden love. Given their work relationship and the nature of Torchwood, their kiss can be seen as something that goes against the rules. Another theme is the emotional release. They've been through a lot together, and the kiss is a way to let out all those pent - up emotions.
One common theme is acceptance. How Ianto and his husband deal with the reactions of others in their world. Another theme could be the building of a family, whether it's through adoption or other means. And often there's the theme of love conquering all, showing that their relationship is strong enough to face any difficulties.
One common theme is survival. Since 'The 100' is set in a harsh world, the pregnancy adds another layer of challenge. The characters have to ensure the survival of the mother and the unborn child in a world full of danger.
Romantic relationships between characters from the two shows are also common. Maybe a character from 'glee' falling in love with a character from 'torchwood'. It allows for a lot of character development and exploration of different personalities coming together.
Character crossovers are also very common. Fans love to see how characters like Percy, Annabeth from Percy Jackson series would interact with Jack Harkness and the other members of Torchwood. These interactions can range from friendly alliances to tense rivalries. For instance, in some fanfictions, there is a competition between the demigods and Torchwood to solve a mystery first.