Orientation

Orientation mediates how intelligent creatures are romantically attracted to one another. Dwarves do not have to be of opposite sexes to be romantically involved or to get married. Same-sex marriages can in fact happen, both in world-gen and in gameplay, albeit more rarely than opposite-sex marriages. Orientation is controlled by the [ORIENTATION] creature token, by default favouring heterosexuality as a majority.

The token takes 4 arguments: [ORIENTATION:<male/female>:<disinterested chance>:<lover-possible chance>:<commitment-possible chance>]. A one-time check is made for each creature to determine orientation, by "rolling a die" once for each sex, against the total of the three chances for that sex. If a given dwarf rolls "disinterested" for the same sex, and "commitment-possible" for the opposite sex, then that dwarf is strictly heterosexual, and is willing to become married. If the dwarf rolls "lover-possible" for each sex, then the dwarf is bisexual, but will never marry, and so on.

The orientation token is omitted from many of the creature definitions and in its absence the game uses some default settings:

• [ORIENTATION:MALE:5:20:75] and [ORIENTATION:FEMALE:75:20:5] for a caste which has the [FEMALE] token under it.
• [ORIENTATION:MALE:75:20:5] and [ORIENTATION:FEMALE:5:20:75] for a caste which has the [MALE] token under it.

It is believed that this pair of default settings generates all populations (including animals) as 71.2% strictly heterosexual, 23.8% bisexual, 3.8% aromantic/asexual, and 1.2% strictly homosexual, though this includes preferences that do not lead to marriage.

Modifying orientation

For more information about how modifying Dwarf Fortress files works, and specifically creature castes, view the Modding page and specifically the Modding#Creature_castes information.

In order to correctly add a custom orientation to any creature, the [ORIENTATION] token with its 4 arguments must be placed beneath at least one of the [CASTE] tokens of that creature. Each [CASTE] only needs one [ORIENTATION] token to function correctly (and the game will indeed only use one per [CASTE] ). Any orientation change to that caste is then immediately effective upon reloading a saved game (if the save file raws were edited) or generating a new world (if the base game raws were edited). Any previously formed relationships in a currently running game world remain intact, however any new relationship interactions are informed by the new orientation settings for that creature caste.

• Adding the tokens [ORIENTATION:MALE:0:0:100][ORIENTATION:FEMALE:100:0:0] beneath the [CASTE:FEMALE] token and [ORIENTATION:FEMALE:0:0:100][ORIENTATION:MALE:100:0:0] beneath the [CASTE:MALE] token would effectively make each caste (and if only those two castes exist, the whole creature) behave exclusively heterosexually with no interest whatsoever toward the same sex, like they did in previous old versions. This can be an important addition for a certain Challenge Fortresses where having children from within the fortress is of vital importance, or simply to ensure that some farm animals (or cave monsters) are always able to reproduce.
• To make the entire creature or just one caste of the creature behave exclusively homosexually, simply apply the [ORIENTATION] token paired with the desired commitment-possible chances to the matching [CASTE]. In effect, apply the heterosexual-only change in reverse.
• Adding [ORIENTATION:MALE:0:0:100][ORIENTATION:FEMALE:0:0:100] to just one caste would effectively make that caste behave bisexually, with every interest in partnering up with anyone. The other unmodified castes would still use their own orientation token setting, or the default if there was no [ORIENTATION] token. Changing the ratio within the tokens from 0:0:100 to 0:100:0 would result in only lovers without marriages.
• Adding [ORIENTATION:MALE:100:0:0][ORIENTATION:FEMALE:100:0:0] to all castes would effectively make the creature behave asexually, with no interest in partnering up and having children (but this would have to be done after world generation by modifying the saved game raw file, or the creature would quickly die out). Gameplay-wise, if the player doesn't want their fortress involved with any children, it would be simpler just to edit the baby/child cap.

A small reminder: As stated on the creature token page regarding [ORIENTATION] the values used are just a ratio, and not an actual percentage. The numbers do not need to add up to any specific number; a setting of 750:200:50 will provide the same effect as 75:20:5 and a setting of 99:99:99 is as valid as 1:1:1.

Nonsapient creatures

Although nonsapient creatures can't marry or even be "interested in commitment", they can still display an homosexual or asexual orientation, which prevents breeding. Since this cannot be easily checked in fortress mode, you just kind of have to hope any creature pair you catch for your breeding program is actually compatible. This behavior can be removed using DFHack's fix-ster script.

Adventure mode

All adventurers are asexual by default and thus cannot ever have marry or have children in vanilla DF, even after retiring them to a site. This can be changed with DFHack's fix-ster script as well, though you will have little control on your retired adventurer's partner choices once they're off-map.