Well, it could be that Harry is cursed by a dark wizard. This curse not only makes him pregnant but also puts his life in danger. His friends, like Hermione and Ron, then have to search for a cure while also protecting Harry from those who might want to use his situation for their own gain. Or it could be a side - effect of a powerful potion he took to gain a new magical ability.
One idea could be that it's a magical accident due to a misfired spell. Maybe Harry was trying to help someone with a fertility spell and it backfired on him. Another could be that it's part of some ancient prophecy where a male must carry a child for a great purpose. And perhaps there's a new type of magic that allows male pregnancy and Harry is the first to experience it in the wizarding world.
One idea could be exploring how Harry copes with the physical and emotional changes. For example, he might struggle with the new limitations his pregnant body has while still trying to be involved in his usual activities like magic training. Another plot could be about the reactions of his friends. Hermione might be super supportive and researching all she can about wizarding pregnancies, while Ron could be initially shocked but then grow to be very protective.
Another plot could be that Charlie and Harry are working on a special project together. During this time, they fall in love and Charlie gets pregnant. But there are outside forces, like a rival group that wants to stop their project. So they not only have to deal with the pregnancy and their relationship but also fend off the threats to their work and future as a family.
One idea could be that they initially struggle with the news. Jamie might be worried about being a good father, while Eddie could be concerned about how it will affect her career. They could then start to plan for the future together, with Jamie becoming more protective of Eddie.
Perhaps in the fanfiction, Nathan and Max are in a world where they are part of a special group or have unique powers. Their pregnancy could be a result of some kind of magical or extraordinary event. They then have to deal with not only the pregnancy but also protecting their unborn child from those who might want to use its potential powers.
Well, perhaps Apollo and Percy are in a secret relationship. The pregnancy could be a result of a magical experiment gone wrong. They then have to hide it from the other demigods and gods. Percy might be worried about how his friends will react, while Apollo is more concerned with the divine implications. They could go on a journey to find a way to reverse it, but along the way, they start to bond more with the unborn child.
One plot idea could be the challenges they face in preparing for the baby while also dealing with their duties in the wizarding world. Maybe there are threats from old enemies who see the upcoming birth as an opportunity to strike. Another idea is that they discover some unique magical abilities that the baby might inherit, leading them on a journey to understand more about their family's magical lineage.
One plot idea could be that it's a magical mishap. Maybe a spell gone wrong during an experiment causes Harry to become pregnant. Another could be a prophecy related to a new kind of magic that can only be carried out through his pregnancy. It could also be a situation where a powerful dark magic is trying to use Harry's unborn child for some evil purpose.
Maybe in the fanfiction, Harry's marriage is a political move within the wizarding world. He marries someone from an important pure - blood family to help unite different factions. This could lead to a lot of drama as he has to deal with the politics and also keep his own values intact.
The plot might involve them trying to keep it a secret at first. Harry would be worried about how it would impact his fight against Voldemort. Tonks, on the other hand, might be excited but also scared. They'd have to figure out how to balance their relationship, the coming baby, and their duties in the wizarding world.
One possible plot could be that it starts with an unexpected encounter between Harry and Gabrielle. Maybe they are in a situation where they have to work closely together, like in a magical mission. As they spend more time together, feelings develop and one thing leads to another, resulting in Gabrielle getting pregnant. Then the story could focus on how they deal with the news, the reactions of their friends and families, and their own fears and hopes for the future.