Talking about the mother events in regard to "NTR" (and again, I mean the F95 'anyone other then the MC fucking girls that the MC fucks' kind of NTR, not netorare NTR), and before you say that is a choice, given that you cannot progress the mothers story without it, it isn't really optional.
It's both a choice, and optional.
You can clearly see what is going to happen when you choose to dose her. She'll be bringing guys home to fuck, all because YOU chose to push her into that mental state.
Nobody forced you, the game doesn't force you, you chose to turn her into the town slut.
Ava has no "story" when you're dosing her. Nor does Dakota.
The story relating to them, is you choosing to use them as unwitting test subjects for a dangerous chemical substance that affects an individual's mental state, allowing them to be pushed toward their fantasies. That's it.
Everything that they do, is because you took the available option of experimenting on them.
Again, avoidable, not optional... all the sissyfication events (events that turn you into a sissy) still happen, you can just avoid becoming one at the very last minute...
They are entirely avoidable, every character has a Dominant stat, just like the lust and love stats. It can go up, and down.
For the Player Character, it's excessively easy to get the Dom stat up, and to stay there, which makes it even more of an option to get any sissy/bimbo content.
you cannot lock your gender, you can say no when a dream happens that would change your gender.
At this point you are either trolling, or need your eyes tested.
There's an option, on the sidebar, called GENDER LOCK. It's a toggle option, on or off.
It's with the same sidebar options that allow you to choose pictures or paper-doll for the avatar image.