I think incest tag was just added and now I am the first of the degenerates to appear. What's the content?
To answer your question directly - so far there isn't any incest with any of the player character's relatives but one of the breeding targets is actually a pair of twin sisters, who you get to have a threesome with. They do a bit of rubbing and kissing together but that's about as far as it goes so far in incest terms. There's probably going to be more with them in the future, though.
It also doesn't completely discount the possibility of incest with the player character's theoretical future daughters with the various breeding targets, especially since there's magic involved so maybe the dev can whip up an excuse to age them up quickly or something - I'd be super into that. Inbreeding is a staple in breeding games!