It is highly unethical. Such a topic involves a non - consensual and extremely harmful act. Fanfiction is a form of creative writing, but this kind of content crosses a moral line. It can also be triggering for those who have experienced or are sensitive to issues of sexual violence.
The idea of Voldemort getting Harry pregnant goes against the original nature and themes of the Harry Potter series. J.K. Rowling's work is mainly about good vs. evil, friendship, and the fight against dark magic. So, while there might be some extremely non - canonical and out - there fanfiction on this very strange and inappropriate topic, it is not something that is in line with the spirit of the original story.
No, it is not ethical. Rape is a serious and traumatic act, and writing fanfiction about it, even in a fictional context, can be extremely distressing and disrespectful to survivors. It also promotes a negative and harmful view of sexual violence.
One negative impact is the psychological harm it can cause to readers. Those who have experienced sexual violence may be retraumatized. Also, it promotes a negative and violent view of relationships.
This is a very disturbing and unethical concept. Rape is a serious crime in real life, and depicting it in fanfiction in such a way is wrong. It can be extremely triggering for survivors of sexual assault and also promotes a negative and inappropriate view of sexual violence.
If Voldemort gets custody of Harry in fanfiction, it would be a huge deviation from the original story. Harry would probably be exposed to a lot of dark and cruel things. Voldemort could try to break Harry's spirit and make him abandon his values. There might be a struggle within Harry between the good he has been taught and the evil that Voldemort represents. And the wizarding world would be in even more chaos as Voldemort would have more control over the one person who was seen as the hope to defeat him.
One negative impact is that it can be triggering for survivors of sexual assault. Reading about such a violent act can bring back painful memories. Also, it can give a wrong message to readers about relationships and consent, as it normalizes non - consensual behavior in a fictional context.
In such a fanfiction, Harry might be used as a bait to lure his friends into a trap. Voldemort could try to extract information from Harry about the Order of the Phoenix or Dumbledore's plans. Maybe he would also attempt to turn Harry to the dark side by showing him the so - called 'power' of the Dark Arts.
In this kind of fanfiction, one possible scenario is that Harry's whole view of the wizarding world would be warped. Voldemort might try to mold Harry into his own image. He could teach Harry dark magic instead of the traditional magic taught at Hogwarts. Harry might grow up with a completely different set of values and powers, which would surely change the whole dynamic of the fight against good and evil in the wizarding world.
In some fanfictions, if Harry Potter gets broken by Voldemort, it could mean his spirit is crushed. Maybe he loses his will to fight and his friends have to find a way to bring him back. It might involve them using powerful magic or memories to reignite his courage.