i asked this question a while back without any answer but it seems theres an event where an npc can trick your character into having sex by persuading you that it isn't really sex which makes your character think they're still a virgin, if they end up getting pregnant they end up confused over how that could have happened to them?
i know that explanation isn't great, i had seen someone talk about it on discord so ill just quote what they said if that helps "iirc you can also get tricked by your lover and that he says X isn't really sex, so you think you're a virgin, and then are confused why you're pregnant" they typed that in response to someone else asking how you can get pregnant while staying a virgin.