With the time jumps we've seen so far all being in increments of 20 years (though that may not account for Ninja Darci, much less for the Shit Ninja (also probably Darci)), the only girl MC could have fathered would be Skylar--but he hasn't had sex with her mother yet. I think it's near-certain it's going to happen (she clearly likes him, and this is after all porn), and that would certainly explain 2019 Luna's reaction to seeing MC, but there are as yet some pieces missing.Is there -based on the actual - update, a chart or some kind that shows the potential incestuous relationships with the time travel involved. Ingame Phonescreen is a bit clunky for that.
For any of the other girls, we'd have to have time jumps of a sort we haven't yet seen. Certainly not impossible though.