gender neutral, definitely. i personally like to headcanon them as nonbinary and they both don't like questions about their genders.
so its like.
"hey frisk! hey chara! what's your genders?"
F: "Determination."
C: "Sin, probably."
"no like. what's in your pants."
F: "??"
C: "A knife."
so its like.
"hey frisk! hey chara! what's your genders?"
F: "Determination."
C: "Sin, probably."
"no like. what's in your pants."
F: "??"
C: "A knife."