Hmm, seems like something that could be added to an existing NPC as an extra quest line. The bunker's already pretty crowded after all. My first thought is actually David, but Sven, Candy, and Icarus are all appropriately "
Uke", even Carl.
My understanding of the fetish is rather limited, but I get the impression it has a preference for "seducing the straight man" and for pregnancy rather than oviposition, so David or Carl are probably the best bet. David apparently has some business involving Brutus (? I never got it to work, but I wasn't trying that hard), but during seduction the dialogue drops hints about "trying to keep him" while he moans and whines about cheating on his girlfriend. On the flip side he's already a pretty involved character, how much do you want to stack on him? Carl was originally expected to be a breeder bitch anyway, but things didn't work out the way Davies had presumed they would.
The more important issue is landing the plot hook in the player's mouth. Dr. Medea seems the simplest target, given that she already avails herself to that particular perk, but right now it requires that you be male.
Or perhaps a completely different track, Brooke loves hot dickings but wants to have babies. That throws all of the above away though...