This trait improves reaction towards the protagonist of members of the opposite sex. Although this often factors into sexual encounters the character may have, this trait can apply to many things happening throughout the game. Through the reaction mechanic, this trait will also affect the prices received from shopkeepers.
The Chosen One's sex rating is measured by primary statistics and optional perks, traits, and reputation titles such as Sex Appeal, Kama Sutra Master, Sexpert, and Gigolo. A calculation of the player character's current stats takes place every time they have sex.
The formula named "obj_sex_rating" in the game files produces a number 1 through 15, the numbers rounding up and down. The higher the number, the more favorable the outcome. Ratings include great (9) required for porn star or gigolo reputation title, good (7), normal (5), bad (3), and horrible (2). The star is the formula is for sex perks, the following of which grant these bonuses to the formula check, including +2 with Kama Sutra Master, +2 if a Sexpert, and +1 with Sex Appeal.
- In the German version of Fallout 2, this trait is replaced by Night Person, even though it has the same image. Fallout has the Night Person trait in the same text position.
- This trait does not exist in the game but an image of a Vault Boy named "SEXAPPL" can be found in the game files of the Fallout demo, corresponding to the Sex Appeal influence skill in Vault 13: A GURPS Post-Nuclear Adventure, the GURPS-based version of Fallout.