The twwo buttons on the right of the screen as you play are both guides. The first is a breakdown of every scene you've been too, and the bottom one is a walkthrough for unlocking corruption.
Corruption is in levels, after a set of events for each character they can progress to the next level, which you can then unlock in the end of run menu for each character.
At higher corruption levels they will becomes significantly more sexual and there will be plenty of opportunities to get them pregnant. Given how the past changes from these, eventually they will arrive at the reunion pregnant.