It could be the result of superstition or misinformation in some very strange and isolated cases. People sometimes spread very odd tales without any scientific basis. It might also be part of some very strange urban legends that get passed around and distorted over time. There's no scientific or rational origin for this kind of story as it defies all known biological facts.
These stories are completely fictional. A woman is a human being and a puppy is an animal, and biologically, it is impossible for a human to give birth to an animal due to the vast differences in our genetic makeup and reproductive systems.
Well, it could be about the challenges Clary faces during childbirth, like her fear and the support she gets from her friends. Maybe her partner is by her side, holding her hand through the pain.
The male and female protagonists in the Nvyūrāsā novels were usually regarded as vulnerable groups and often suffered all kinds of injustice and discrimination. They were often portrayed as weak, helpless, and incompetent, often needing the help and care of female characters. These characters usually exist to express the superiority and power of female characters and the inferiority and incompetence of male characters. In the setting of a female character giving birth to a male character, there was often gender discrimination and injustice, resulting in male characters being restricted and treated unfairly in certain aspects. These plots were often used to emphasize the power and status of female characters and the helplessness and weakness of male characters. Although the existence of a female god, a male god, and a male god might express some ideas of gender equality, there were usually some situations of equality and discrimination in their plots and character settings.
The plot could also involve the father of the baby being a mysterious figure. Maybe he's from a far - off land that Elsa visited during her adventures after the events of the Frozen movies. And as she gives birth, the baby could inherit some of her ice powers, which would lead to a whole new set of challenges and adventures for Elsa as a mother, like teaching the baby to control its powers from a very young age.
One possible plot could be that Sakura has a difficult birth. Naruto is by her side, worried sick. Their friends from the village are also there, waiting anxiously. Maybe there are some complications during the birth, and Sakura has to draw on her inner strength as a kunoichi. And in the end, she gives birth to a healthy baby, which brings great joy to the whole village.
Perhaps it could involve some sort of magical or scientific experiment gone wrong that results in Tony being able to give birth. Peter could be the result of a genetic manipulation within Tony's body, and the story might then focus on how they adapt to this strange new situation.
Maybe in the fanfic, Annabeth is in a situation where she has to give birth alone in a dangerous place. She could be on a quest when she goes into labor prematurely. She uses her wits and knowledge of survival to ensure the safety of herself and her baby. It could show her strength not just as a demigod, but as a mother - to - be.
One possible storyline could be that Twilight Sparkle gives birth to a magical foal with unique powers. Maybe the foal inherits Twilight's love for knowledge and has an instant connection to the magic of Equestria. The story could then focus on Twilight raising the foal and teaching it about friendship and magic.
Perhaps the fanfiction focuses on how the baby changes the relationships in Naruto's life. Her relationship with Sasuke could be affected, whether they are friends or something more. The baby could also bring new unity among the ninja villages as everyone comes together to protect the new life. And the story could explore how female Naruto passes on her ninja values to her child from a very young age.
One possible plot could be that Rachel gives birth during a big performance. Maybe she has been hiding her pregnancy from most of the glee club members, and right in the middle of a huge show, her water breaks. This leads to a chaotic but heartwarming situation where her friends rally around her, turning the backstage area into an impromptu delivery room while still trying to keep the show going in some way outside.