|This article is about the current version of DF.|
Two dwarves can get married after having a romantic relationship together. Instantly after marriage, those dwarves usually throw a wedding party if there is an available room, such as a statue garden, or a dining room marked as a meeting hall. Dwarves marry for life; a dwarf whose spouse dies will not remarry. The death of a spouse will give a dwarf an unhappy thought. Dwarves will cancel their current task when getting married.
Dwarves must be within 10 years of each other in age, and must not be children or babies, to enter into a romantic relationship. Being friends may be a prerequisite as well. The 10-year restriction only applies in fortress mode, so incoming pregenerated dwarves (i.e. migrants) may have a larger gap between their ages. No marriage between siblings has been observed, but cousins or other distant relatives can marry each other.
Dwarves with similar professions are more likely to get married, presumably because they spend more time together than with dwarves they meet otherwise. For example, two miners are likely to become romantically involved, especially in a fort with sporadic mining, since they will be "off work" at the same time and spend that time together frequently.
To enter into a romantic relationship, dwarves must be allowed to idle together in the same room. They will then socialize and build relationships. If they are compatible in terms of age and marital status, they will eventually become lovers and then marry. If not, they will simply become friends. Dwarves with too little free time will not have time for romance. Occasionally, a couple may stay in the "Lover" stage perpetually without ever being married or breaking off the relationship.
Married dwarves may sleep together. Because of this, the couple only requires one bed, and any bedroom claimed by or assigned to one spouse will automatically be assigned to both. This also applies to tables, if they are assigned specifically to a dwarf.
In a heterosexual couple, the wife will become pregnant every year, until she or her husband dies, or until the fortress's child limit (or strict population cap) is reached. There are no visible signs of pregnancy, and the only effective means of contraception (other than the aforementioned limits) is physical isolation. However, that doesn't mean a pregnancy will always result in a baby. Pregnancies may end in miscarriage if the dwarf is starving, dehydrated, sustains an injury, etc., which can lead to tantrums from your now miserable dwarf and possibly a downward spiral of fun.
Many marriages seem to occur during springtime or early summer.
 Arranging marriages
Dwarves are quite slow to form close relationships; several years of non-stop socialization may only form one or two romantic couples. For overseers who want children (possibly because their civilization is extinct), a more proactive approach is often necessary. A good first step is to determine which dwarves are compatible (within 10 years of age and willing to marry). Once you have selected couples, the next step is to cause them to idle next to each other as frequently as possible. This can be achieved by assigning them to special "pre-honeymoon" suites containing two beds (each defining a bedroom), enough fancy furniture to make the rooms high-quality, and impassable furniture (statues) to prevent the owners from avoiding each other. (Designate the rooms *before* adding the statues, since you can't designate a room through them.) Reduce your chosen dwarves' workloads and disable all meeting areas (including sculpture gardens, zoos, etc.) to force them to idle in their shared bedroom as much as possible. Note that locking them into the room may be counterproductive since it limits the number of "encounters". With a proper setup your dwarves should be married in a matter of months.
 Sexual orientation
Dwarves do not have to be of opposite sexes to be romantically involved or to get married. Gay marriages can in fact happen, both in world-gen and in gameplay, albeit more rarely than heterosexual marriages. Sexual/Romantic 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 tag is omitted by default, and in its absence the game uses the values
[ORIENTATION:FEMALE:75:20:5] for the female caste, and the reverse for the male caste. It is believed that this makes 71.2% of dwarves strictly heterosexual, 23.8% bisexual, 3.8% aromantic/asexual, and 1.2% strictly homosexual, though this includes preferences that do not lead to marriage.
[ORIENTATION:FEMALE:100:0:0] to both castes would effectively make them behave asexually, with no interest in partnering up and having children (but this would have to be done after world generation, or dwarves would quickly die out). Gameplay-wise, if one doesn't want to take care of children in fortress mode, it would be simpler just to edit the baby/child cap.