When creating your character, you may choose a gender: male or female. This affects a number of events in the game:
- Female characters can lay eggs when polymorphed into a monster that lays eggs
- Any eggs found and carried by male characters have a 50/50 chance of hatching tame. Eggs found and carried by females never hatch tame. (Eggs laid by you always hatch tame, regardless of your current gender.)
- Male characters are seduced by the succubus, female characters by the incubus. During seduction, incubi will put a ring of adornment on your hand if you have one, while succubi will steal them.
- Male characters are "seduced" by nymphs, while female characters are "charmed".
- Female characters get slightly more matching foocubi from gating.
Monsters can be gendered (including neuter), but this affects only the pronoun used to relate their actions.
In SLASH'EM, Yeomen always start as male.
In Slash'EM Extended, the player character's gender has some more effects:
- Male characters can be kicked in the nuts by a monster that uses kicking attacks, suffering (2dX)+1 extra damage (where X is the monster's level). If the player dies from it, the tombstone message reads "killed by a kick in the nuts".
- Female characters can be ripped into their breasts by a monster that uses claw attacks, suffering (2dX)+1 extra damage (where X is the monster's level). If the player dies from it, the tombstone message reads "killed by a cowardly attack on her breasts".
- If a male character gets his items stolen by a female monster, he may lose a point of charisma. The chance that this type of theft attack is successful is 80%.
- If a female character gets her items stolen by a male monster, she may lose a point of wisdom. The chance that this type of theft attack is successful is 66%.
- If a character gets their items stolen by a monster of the same gender, the theft attack has a 50% chance of success and cannot reduce stats.
Since the claw attack appears much more often than the kick attack, female characters are in more danger of suffering extra damage. However, most item-stealing monsters (especially nymphs) are usually female, so a male character suffers from stat loss more often.
Recent Slash'EM Extended versions display the character's gender in the status line: "Mal" for male characters and "Fem" for females.
In SpliceHack, the player's interactions with succubi and incubi are not determined by their gender, but instead by their sexuality. Additionally, players may elect to play as nonbinary. A nonbinary player character is unique in the following ways:
- Nonbinary characters are more likely to receive armor removal prompts when being seduced by a monster.
- Nonbinary characters can't lay eggs.
- Eggs that hatch in the inventory of a nonbinary character always produce peaceful monsters.
- Nonbinary characters cannot be seduced by succubi or incubi, unless the player character is bisexual.