Fallout 4 allows you to romance non-player characters regardless of your character's gender — implying that all characters are playersexual.

Playersexuality is when non-player characters in an otherwise heteronormative video game are romantically interested in the player regardless of the characters' genders.[1]

Playersexuality in video games constitutes bisexual and generally polysexual erasure in many cases.[2] Playersexual characters do not self-identify with a sexuality, do not have a sexual history or have a heterosexual one, and are found in heteronormative worlds.[3]

Playersexuality does not actually promote diversity in games at all. To quote Shaw (2015), these methods of incorporating marginalised perspectives are in fact a form of ‘pluralism’, not diversity. They expect players to be responsible for the labour of incorporating non-normative characters, and because these players are not forced to experience new perspectives, this implementation does not allow games to have transformative, educational effects more broadly. This applies not only to diverse sexualities, but all forms of diversity where the player is responsible for whether or not it is seen in-game.[1]