Hello Hello fellow degenerates! I am a fan of Incestuous games, and well, games where you develop relationships are all well and good, but is there one where you impregnate family members, and see the result?
Most devs draw a pretty hard line against this as you may well know. One of the best examples is perhaps Corruption of Champions where you can have spawn but the devs decided against any content with the MC and them.
In that same tradition CoC 2 follows the same path but unfortunately has similar limitations.
You're pretty much going up against a hard limit there