Well I don't think a game can fix what people missed in school sooooIf people base their knowledge about birth control on porn games, god help them, because we cannot help them.
The idea that coming outside is effective birth control is so often used in the adult games, that it's just a trope at this point. I always understood it as a way from the dev to ask whether the player wants pregnancy or not (if the woman is not on real birth control pills), without resorting to actually asking to enable pregnancy or not. Even birth control pills have a non- negligible chance to fail to prevent pregnancy (something like 3-4% chance).