CW: emetophobia... sorry Indy's gross :(
Started thinking about the likelihood that these two would wind up with a child at some point in scifi AU, maybe a year or two post-epilogue. Pen had always assumed a family would remain out of reach for him; ironically, it feels like a more tangible possibility after getting hitched with a man of a different species.
He doesn't know if kids are even something Indy would want, but living with a yotie pack and being surrounded by families communally raising pups at all life stages eventually gives Pen significant enough baby fever to ask him about it.
For Indy's part, he had never thought he'd be cut out for this kind of responsibility, but he does like kids and Pen seems to have faith in him, so he asks around at nearby packs; yoties live in harsh environments and even new mothers will join in on hunting parties and contracts, so it's not unusual for a pack to have an orphaned pup in need of a new caretaker. It couldn't hurt to ask, just hypothetically, right?
And that's how they wind up "temporarily" responsible for the care of a sickly newborn pup. Pen tries not to get attached and fails immediately. Even knowing the baby is a "runt," he's not prepared for how small and fragile a canine newborn is, nevermind the fact that they're blind and deaf for the first months of life. How could something so helpless and tiny grow into a... well... Indy???