Hello!
The short answer is that there are customisation options for gender outside of just the apperance.
To clarify, the statement when I say "pre-defined personality and history", this is not referring to the character's gender identity at al!
The "pre-defined personality" referring to their literal base personality traits (calm, brave, observant, anxious) and their literal backstory ("raised in a spooky tower by a Witch"). These two elements are not customisable and are also not connected to the character's gender. They are a part of who this person is regardless of what other options the player chooses.
The customisable elements include:
Visual Elements:
- Body shape (out of four options)
- facial shape (out of two options)
- hair colour (out of 6)
- skin tone (out of 6)
Story Elements:
- Pronouns + Verbs
- Titles/Other nouns (daughter/son/child, etc)
- First name
Story wording does change sometimes based on these options so the story is not written in a way that assumes a gender neutral state. This can be as minor as who leads if the MC is dancing with a love interest or it can change certain aspects of how a love scene plays out.
Hope this helps.