I've been thinking about a story where a guy/gal goes back in time and has sex with someone from their parents line. Could be young (legal) mom or dad or even going way farther and fucking young (legal) grandparents. It could also involve some "dark" parts where the character on purpose or accidentally knocks up the character from the past which rewrites history or the character ends up being responsible for something like the birth of his sister or even himself/herself. It could even go some other route where the character had a sister/brother when they were young but the sibling ran away. The character wanted to know what their sibling was like and go back in time to meet them but accidentally (by mistaking identity) or on purpose has sex with them and in turn becomes the reason for their sibling running away. It could also go in a completely different route where the character travels back in time but because of time travel rules, the character is now stuck in their parents body or grandparents body (male or female). Or the character just has cimpcomple fucked up dark intentions and wants to knock up every single woman from his mother's line. I've been thinking about this idea for months now. I'm not sure if others would like it or think it's too "fucked up". I would love to know what you guys think of it. I looked online for similar stories but I guess it's too specific of a fantasy that there aren't many stories written on it.
You sure you searched hard enough of a similar story? Cause what you are suggesting sounds like a futurame episode. At some point, Fry and the gang travel back in time to an era his grandparents were alive. He tries to prevent his grandfather from dying, but instead gets him killed. Due to this he is convinced his supposed grandmother (in her 20's) is not really his granmother and so her makes love to her. Only to then discover she really is going to become his grandmother, meaning Fry basically became his own grandfather.
As someone big into both impregnation and incest I would be definitely interested in something like this! A fun idea could be to have the MC manage to create an entire dynasty from the distant past, impregnating his daughter and then her daughter and so on. Presumably minus any chance of issues, of course! Or alternatively getting his mother in the past pregnant enough times to have dozens of sisters/daughters. So I think it could work well as a story.
