The thought police will come after you no matter what you say, or who your characters are.
I think as a writer, you could clearly state there was some guilt, and regretfully bad decisions made on the part of the MC and their partner if someone ended up getting knocked up when one or both the partners were underage. Someone's gonna get pissed at that, but they can pound sand. I mean, they are on a pirate site for porn games. They don't have a lot of moral ground to stand on. In fact, there's a mainstream Adam Sandler movie (That's my Boy) where the MC's dad had him with an adult teacher when he was underage - though the teacher did end up in jail for it.
Its certainly a better premise than the characters waited for the magical age of 18 to ever have sex, and then suddenly made a bad decision to not use protection.
I personally don't have any problem with the MC having been 14, banging a teacher, neighbor, older brother's ex girlfriend, or even a close relative like a mother or aunt. You can talk about it a few times in game, and most people will probably skip over it.