Yeah, there's that. But when the MC was isekai'd, Lily had already been born. So, this should have been caused by another reason instead of being impacted by his actions.There's no fancy reason, it's an extremely common isekai trope that 'the game/manga/anime was a guideline but not eveything is 1-to-1 with it in 'real' life'. Honestly, MC should've realized this far sooner because of everything that's already changed, he's just a dumbass.