Feminity
Feminity is an unique body stat represented on a scale of 0 to 100. 0% means the character is perfectly masculine; exactly 50% means the character is completely androgynous; 100% means the character is perfectly feminine.
0 to 50 exclusive: Masculine Exactly 50: Androgynous 50 exclusive to 100: Feminine (Note: If you have time, feel free to use a CSS gradient to emphasize on the progressive aspect of the scale.)
Many scenes require a certain degree of feminity (or "non-feminity", aka masculinity) to be unlocked. Likewise, some NPCs will refuse to interact with the PC if feminity is too low or too high.
Feminity is not directly affected by muscular tone or thickness. However, it will be adjusted if hormonal changes occur in the player's body due to certain substances like Bimbo Liqueur and Bro Brew or if the player has the Futa Faculties/Futa Form herm perks.