Viktor had a child when he was teenager, go as young as you dare. (can be a/b/o, can be whatever, I'd prefer it to not be genderswap)

BONUS POINTS: he and the kid have a good relationship.
DOUBLE BONUS POINTS: he was in denial and competed through most of the pregnancy. It was angsty and painful.
ALL THE BONUS POINTS: Yuuri's the first person Viktor admits to how impossibly hard it was and doesn't put up a brave mask for.