If there is any small annoyance I have with this game it's that the blackmailing gym teacher, who was obsessed with Celesphonia's mom to the point he specifically targets Celes, is such a stickler for safe sex and using condoms. It ruined my concept of having my 'first run' Celes end up falling for his blackmail and having his kid before going full dark magical girl out from the emotional pain, and then doing a final virgin run with their daughter still being in the book-realm as a grim reminder of the past.
The situation with the gym teacher is one of the more interesting setups and makes the most sense for a pure Celesphonia to fall into, because it's out of concern for her best friend, and will often play out pretty far before she can realise said-bff is already tanking her own reputation blackmail material aside. It also has a little extra spice because it's her civilian identity where she has no power.
If anyone does do a full-scale pregnancy mod it would be neat if the gym teacher specifically didn't use a condom the first time, even if he did after that. All that would need to be changed would be a small portion of the CG, as the only evidence he uses one is that it gets placed on the ground in the top corner afterwards.