So Luke (and preferably Leia + Han) get captured and Vader is informed that the prisoner is pregnant.
Turns out Han + Luke (whether established relationship/one night stand/multiple one nights stands/friends with benefits/I don't care) messed around a some point and now Luke is pregnant (maybe they didn't know he could get pregnant because it's rare in males IDK).
Now Vader has to deal with the fact he's (probably) going to be a grandfather while also dealing with the fact that the Empire wants to exploit the pregnancy for their own gains (/just kill Luke so he doesn't create a new potential threat)
mpreg - Han/Luke - Vader dealing with the fact he's going to be a granddad
Turns out Han + Luke (whether established relationship/one night stand/multiple one nights stands/friends with benefits/I don't care) messed around a some point and now Luke is pregnant (maybe they didn't know he could get pregnant because it's rare in males IDK).
Now Vader has to deal with the fact he's (probably) going to be a grandfather while also dealing with the fact that the Empire wants to exploit the pregnancy for their own gains (/just kill Luke so he doesn't create a new potential threat)