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Reproduction is the means by which human babies are created.
Note: Due to the continuous nature of the subject matter, this page covers from conception to the age of three.
- 1 Acquisition
- 2 Natural reproduction
- 3 Assisted reproduction
- 4 Birth
- 5 Heredity
- 6 Fertility
- 7 Contraceptives
- 8 Babies
- 9 Version history
|This section is suggested to be moved. Destination: Babies. Reason: We've discussed moving the Babies and Acquisition sections to a new Babies page since there's a lot of content here and reproduction and Babies are two separate topics.|
Babies can be obtained via several different methods:
- Choosing them as a starting colonist via the scenario system.
- Natural reproduction, through pregnancy.
- Assisted reproduction, through surrogacy or growth vats.
- Purchasing them from slavers.
- Receiving them from quests and events. Babies of any faction can be adopted instantly to the colony, without angering them.
Note that with the exception of the first point, these methods become unavailable if "Disable children" is toggled on in the storyteller settings.
|This section could use some more or updated images. You can help RimWorld Wiki by uploading images to make this section better. Note: Images of the "Try for pregnancy" etc. icons..|
Pawns in romantic relationships have a chance to get pregnant when they initiate lovin'. Note that pawns must share a two-person bed, bedroll, or sleeping spot to initate lovin' but do not require one to avoid the "sleeping alone" mood debuff.
The prospective parents' chance of successfully reproducing is primarily controlled by their Fertility stat. The player has three options to adjust pregnancy rates from Lovin' in any relationship. By opening the social tab, to the right of a Lover, Fiancee, or Spouse, you can see a button that lets you change the couple's approach for having kids.
|Normal (Default)||x1 pregnancy chance.|
|Avoid pregnancy||x0.25 pregnancy chance.|
|Try for baby||x4 pregnancy chance.|
Therefore, the total chance of pregnancy in one relationship is likely:
|Pregnancy chance per relationship = Mother's fertility x Father's fertility x Reproductive Approach x Times Lovin'|
The actual chance that a pair of pawns will do Lovin' each night varies, but it requires them to share the same bed and sleep at the same time. Their chance of Lovin' varies by age, as seen in this chart. The low libido and high libido genes will also alter this. There have been reports that colonist mood and opinions of each other also influence the chance of doing Lovin'.
Pregnancy lasts for 18 days, broken into three 6 day trimesters. The player will receive a notification when the pregnancy starts and when it progresses from one trimester to the next. The pregnant pawn will gain penalties to movement, manipulation, and hunger rate, increasing each trimester as seen in the chart below. Other than limitations due to movement, pregnant pawns have no restrictions on the activities they pursue.
During the first trimester, a pawn will gain the New pregnancy moodlet, which can either be positive or negative direction: +3, or −3 I'm pregnant and not very happy about it. The same pawn can feel differently about different pregnancies. Throughout their pregnancy, they will also occasionally gain mood buffs or debuffs due to hormone-induced mood swings. Mood swings are visible in the Health tab as a condition affecting the brain. They vary in severity, direction, and duration, appearing as: "Pregnancy Mood (<duration>, <type>)" with the description This common side effect of pregnancy represents a rising and falling mood caused by unbalanced hormones. Accompanying this, the pawn will get a positive or negative moodlet labeled Pregnancy mood <type>. Mood swings are short-lived, with the longest duration seen so far being 10 hours.
Types of Mood swings:
- High: ?
- Down: −8 It feels like everything is going wrong for me today. Pregnancy is tough.
Pregnant pawns may also receive the "morning sickness" condition, which lasts 4 to 8 ingame hours. Along with health effects, they will gain the −3 mood debuff Sick.
Note that Pawns in the character selection menu can begin the game already pregnant.
Science enables new methods for obtaining babies. After Fertility Procedures has been researched, you can extract ova from female pawns and fertilize them to form an embryo, for use in surrogate pregnancies or vat-grown babies.
Both methods require extracting an ovum from a fertile female pawn, be they colonist, prisoner, or slave, through a medical operation in the pawn's Health tab: "Extract ovum for IVF". The operation requires one of any type of medicine and a doctor, although it is a relatively easy surgery, with a 500% multiplier on success, and 0% chance of death on failure.
The ovum may then fertilized by a fertile male colonist or slave (but not prisoner) to produce an embryo. As long as the male pawn's fertility is above 0% this will be successful. The resulting embryo can then be implanted in female pawns (may be prisoner, colonist, or slave) to initiate a pregnancy, placed in a growth vat, or sold.
With the Fertillity Procedures research, you can create embryos. They can then be implanted into a pawn for a chance for the pawn to become pregnant. The chance of success depends on the surrogate's own Fertility.
Even if they did not supply the ovum, the surrogate will be considered the birth mother. Otherwise, it will act as a regular pregnancy.. A pawn born this way will consider both their surrogate and genetic mother as the pawn's parents in terms of social opinions.
Growth vats allow an embryo to be born in 9 days, half the time of a natural pregnancy. Active vats must be given a constant supply of 200 W of power and 6 nutrition per day - or around 6.5 simple meals per day - to ensure survival of the fetus. If lacking either, then the fetus will undergo biostarvation, increasing by 50% per day. If biostarvation reaches 100%, the fetus will be destroyed.
Growth vat births always have a quality of 70%, which affects the chance of the baby being born healthy. However, there are benefits to this method: as it avoids natural birth, the mother won't be weighed down, and there is no risk of them dying.
Your first warning for a pawn's upcoming childbirth comes during a pawn's pregnancy: the player will receive one notification when the mother hits the third trimester about "<Colonist>'s baby prep", which explains all the steps you can take to help the mother give birth successfully. Besides preparing a location and doctor for the birth, this notification reminds you to prepare a food source for the baby and build them a crib. Labor will happen roughly 6 days after, starting with a notification of "<Colonist> in labor!".
Once labor begins, the birthing procedure can be initiated by clicking on the mother, and selecting the "Begin birth" option. This allows the player to select participants and a Doctor, much like Ideology's rituals. The procedure will take place at a bed or sleeping spot, chosen automatically (preferring medical beds) if the mother is not already in bed. All of these choices have an effect on the birth's quality, which affects the chance that the mother and baby will come out of childbirth alive and healthy. You can view the exact factors and their influence in the Quality section below. The expected duration of this operation is variable, but will end once the baby has been born or mother has died.
The progress of labor can be tracked in the mother's health tab. Labor begins with contractions, different stages of dilation that change randomly over time, with all adding various amounts of pain and restrictions on movement for the mother. Many stages will incapacitate her, so even before the childbirth operation begins, it is important to bring her to a bed. When the childbirth operation has proceeded for a while, you will receive a small notification saying "<mother>'s labor has entered the final stage", and the labor will progress to the final "pushing" stage.
Stages of labor:
- dilation, mild: pain +25%, moving x40%
- dilation, debilitating: pain +85%
- pushing: pain +85%
Once the childbirth procedure has begun, any spectating loved ones may socialize with each other, but the doctor and mother will be focused on their tasks. Spectators and the doctors can leave if needed, by selecting a pawn and then pressing the "Leave child birth" option. Finally, you can cancel the birth operation by selecting any of the involved pawns and then selecting the "Cancel child birth" option, which allows you to restart childbirth later.
When starting the child birth procedure, a screen will show you the expected quality of the birth, determined by:
- Loved one present: the presence of someone that the mother considers a friend or more gives +5% quality, with no stacking for multiple friends or a better friend. By default, the father will be selected to be present. If the doctor performing the operation is a friend, they will count towards this bonus too.
- Age of the mother: a 22-year-old has a +50% quality, and as the mother grows older, this drops.
- Doctor's medical skill: can range from 0-20% or more. Skill level 1 gives 1.3%, 3 gives +3.8%, 7 gives +8.8%, and 16 gives +20% quality.
- Indoors: if inside, the quality gains +5%.
- Room cleanliness: cleanliness can range from 0-0.6, giving 0-10% in quality bonuses.
- Bed health effects: contributes up to 5%, with things like bed quality, a medical bed, and (perhaps vitals monitor or other furniture?) influencing this stat. A bed rating of 5 guarantees a quality bonus of +5%.
Therefore, the most important factors in a safe birth are the mother's age and the doctor's skill level.
Birth quality is likely determined at the moment of the baby's birth; allowing the doctor or loved ones to leave, or having the room grow dirty, has an effect on birth quality.
|This section is a stub. You can help RimWorld Wiki by expanding it. Reason: Exact math on the chance mechanics.|
Depending on the quality, the baby can be born healthy or sickly, or they may die during birth. At lower qualities, there is also a chance that the mother can die during childbirth.
You will receive a notification when the birth is complete, and the baby will appear on an adjacent tile. If the baby was born alive, a pawn with the Childcare work enabled can be instructed to either move the baby to a safe space, or to deliver it to the mother for breastfeeding. The baby will be born hungry, with a mood penalty of −6.
If your baby was healthy, the notification is "Healthy child birth", and it gives you 24 hours to choose a name for the baby. This is the only time where you can completely customize the baby's first and last names, and you additionally can add an optional nickname. The game will suggest the mother and father's last names on this screen, and provide random suggestions for the other names. Until then, the baby's name is temporary, and called "Baby <Mother's last name>". The baby will also receive the Childhood title "Newborn", and belong to the mother's faction. The baby's parents will receive a 15-day mood boost that "<Baby> was born healthy" +8.
If the baby is born sick, they are affected by a form of infant illness, which can start at a variable intensity. If left untreated before 10 days is up, the baby dies, but if it lives through 10 days after birth, the illness will no longer affect the baby. You will also get the chance to name your baby.
If the mother survived childbirth, she will remain in bed, incapacitated by exhaustion (Postpartum exhaustion) for 16 hours. She'll no longer feel any pain from childbirth, but won't be able to move. However, if another pawn delivers her baby to her, she can begin breastfeeding.
Upon a successful natural childbirth, the birthing mother will begin lactating. A lactating pawn can breastfeed babies, even if not their own. Lactation lasts indefinitely, but stops after 10 days of not breastfeeding a baby.
While lactating, the pawn gains a milk fullness stat, which starts at 100%. When it is above 0%, a pawn can breastfeed any baby, reducing milk accordingly. If it is below 100%, then the mother's Food Consumption increases. Consumption increases by up to +0.5 nutrition per day, for a total of 2.1 nutrition per day, until milk is full. For reference, 1 simple meal is 0.9 nutrition. This scales with milk regeneration rate, which decreases as the pawn gets hungry.
|Hunger Level||Malnourished||Ravenously hungry||Hungry||Full|
|Extra Nutrition Per Day||0||0.13||0.25||0.5|
Lactation also multiplies Fertility by ×5%, meaning the mother is very unlikely to get pregnant, naturally.
When an embryo is conceived, it will inherit some of the genes of both parents. During a mother's pregnancy, you can view her child's genes by going to her Health tab and selecting the information button for her pregnancy. The genetics section will list all genes that her child has inherited.
Genes which can be passed down come from the germline DNA, and are called endogenes. Pawns may modify themselves with xenogenes, but as it's not part of a pawn's germline DNA, it cannot be passed down. If an endogene is only present in one parent, it has a small chance to be passed down. However if an endogene is present in both parents, it will always be passed down.
Generally, all pawns will have at least one hair color and skin color endogene. Offspring will always pick one hair color and skin color endogene from their parents. If no hair/skin color endogene can be found in either parent, such as if they were two highmates, a random hair/skin color endogene will be picked from the natural list of hair/skin colors instead.
If a pawn has multiple cosmetic genes within a category, like body type, one random gene will override the others. This will be the gene represented on the pawn. For non-cosmetic genes within a category there is a fixed priority for overrides, usually favored towards the negative variations. For example, an awful shooting aptitude will override all other shooting aptitudes. Xenogenes will always take priority over endogenes. Thus, even though the Slow runner endogene overrides their Fast runner endogene, the Fast runner xenogene will override the Slow runner endogene. Note that overridden endogenes can still be passed down as normal.
If a child is born from an incestuous relationship, there's a risk of them becoming inbred. The likelihood of this is modelled proportionally to the pawns' coefficient of relationship, though it is largely simplified.
As a general rule, the risk is 80% for first-degree, 40% for second-degree, and 10% for third-degree relatives; however some exceptions apply, an example being 20% for cousins. Many fourth-degree relationships and beyond are simply referred to as "Kin". Kin relationships pose no risk for inbreeding, despite being considered incestuous. If two pawns are related in more ways than one, such as being both parent/child (80%) and grandparent/grandchild (40%), the highest number always takes priority when calculating inbreeding. Pawns being inbred will not directly increase this number, but since inbred is a gene it will follow the same rules of gene inheritance as all other genes.
It's possible to check for the inbred gene after conception by using the "Inspect baby genes..." button on the pregnant pawn or the embryo. The outcome of a pregnancy isn't affected by inbreeding, but should the baby be born, the game will display an additional line in the birth results:
The baby shows signs of genetic abnormalities due to inbreeding.
The risk of inbreeding goes as follows, higher numbers taking priority over lower ones:
|Relation||Inbreeding risk||Coefficient of relationship|
|G. grandparent/Grandaunt/Granduncle/Grandniece/Grandnephew/G. grandchild||10%||12.5%|
|Half grandniece/Half grandnephew/Cousin once removed||10%||6.25%|
- Although birth parents are considered on the same level as biological parents, they aren't genetically related to the child they birth, and thus run no risk of inbreeding despite the game's warnings that they do.
Fertility is the main pawn stat affecting pregnancy chances, acting as a percentage multiplier on the chance of getting pregnant naturally or through an ovum implantation. Natural pregnancy chance is equally dependent on the fertility of both partners. Additionally, fertility must be above 0% to extract a pawn's ovum or to fertilize the ovum into an embryo.
This stat is affected by a variety of factors, such as age, genes, and contraceptives. Age is the baseline for fertility, changing slowly for each colonist over time, and at a different rate by pawn gender. Genes provide an additional multiplier on fertility. Contraceptives instantly bring fertility to 0%, overriding other fertility factors.
For baseline humans without fertility-modifying genes, both men and women start becoming fertile after age 14; but regardless of fertility, pawns can't participate in reproduction until they are 16. Fertility increases differently by gender. Women's fertility increases until age 20, but starts dropping at age 28 until it reaches 0% at age 50. Men's fertility increases until age 18, but starts dropping at age 50 until it's 0% at age 90.
Genes affect fertility in direct and indirect ways. There are two direct effects: the Fertile gene doubles fertility and the Sterile gene completely nullifies it. The Ageless gene prevents aging entirely, which prevents fertillity loss. Age Reversal also has a fully restorative effect on fertillity. Even a completely infertile pawn (due to age) can start reproduction again.
There are many ways to manually change the likelihood of natural pregnancy. The simplest way in the game to prevent pregnancy is to not give pawns a double bed to themselves. However, it deprives them of the mood bonuses of Lovin' in the first place. By changing a couple's Reproductive Approach "Avoid pregnancy" in the social tab, pregnancy rate will be reduced by −75%, but still gives Lovin' at the same rate. Lactation, from having given birth before, gives a ×5% multiplier to Fertility.
A more stable way to prevent pregnancy is available from the Fertility Procedures research. This gives access to multiple operations, temporary or permanent, to prevent and stop pregnancies. These surgeries can be applied to any pawn age 16 and up, and can be performed even if the pawn is already infertile.
This is a temporary method of preventing pregnancies. You can stop a female pawn from becoming pregnant with the "Implant IUD" medical operation, which has a base 100% success chance and no chance of pawn death upon failure. The operation requires 1 Medicine of any type and will anesthetize the pawn. The IUD lasts indefinitely and can be seen in the pawn's Health tab, but you can later remove it through the "Remove IUD" medical operation, also for 1 Medicine of any type. Women may embark with IUDs already implanted. If either of these operations is botched, the patient will become permanently sterile.
Implanted IUDs also stop pregnancies in the first trimester, an alternative to the Terminate Pregnancy operation.
This is another temporary method of preventing pregnancies. You can stop a male pawn from impregnating others with the "Perform vasectomy" medical operation, which also has a base 100% success chance with no chance of pawn death upon failure. The vasectomy lasts indefinitely, with the operation requiring 1 Medicine of any type. You can later remove it through the "Reverse vasectomy" medical operation, also for and 1 Medicine of any type. Men may embark with the operation already performed. If either of these operations is botched, the patient will become permanently sterile.
This permanently stops a female pawn from being able to reproduce. "Perform tubal ligation" is a medical operation requiring 1 Medicine of any type. The surgery success chance is 100% and there is no chance of pawn death upon failure.
If the pawn has already become pregnant past the first trimester, the only option left is to terminate the pregnancy. This can be achieved through the medical operation "Terminate pregnancy" requiring 2 Medicine, after which the pawn will no longer be pregnant.
This operation will upset the affected pawn. Depending on the trimester of the pregnancy, a moodlet of −5 for the first, −10 for the second, and −20 for the third will occur, lasting for 10 days.
|This section is suggested to be moved. Destination: Babies. Reason: We've discussed moving the Babies and Acquisition sections to a new Babies page since there's a lot of content here and reproduction and Babies are two separate topics.|
The end result of pregnancy is a human baby. Babies are small, helpless creatures that cannot walk or do anything by themselves. They only have three basic needs: food, sleep, and play.
Babies can be ages 0-2, with newborn ages tracked in days and quadrums rather than years. Once a baby turns 3, they become a child, and on their 3rd birthday you can make special choices for how they will develop further. Under the default storyteller settings, pawns under 13 will age 4x faster than normal, so the biological age of the baby is not how many days/quadrums they have actually been alive. Growth vats can speed up a baby's growth by 20x that of an adult, or 5x faster than default. Using a growth vat seems to have no ill effects on a baby or its development, at least until it exits the baby stage. However, parents gain a −4 My baby is in a growth vat moodlet.
If a baby is left on the ground, any colonist (even those incapable of childcare or hauling) can try to bring the baby somewhere safe, like an available crib. Usually a colonist will quickly try to do this automatically. If you draft a colonist while they are carrying a baby, you'll receive a pop-up warning that your colonist is carrying a baby while drafted. If you undraft and redraft the colonist, they will drop the baby.
Babies are born with no traits or skills: these develop during childhood Growth Moments. They also have no ideoligion . Unless they have temporary health effects from being born sick, they have no health conditions, with every health stat at 100%, except for Moving, which is at 0%.
Babies need less nutrition to become full, but their hunger rate is adjusted with it to require food twice a day. Since babies cannot eat anything by themselves, pawns assigned to childcare will help feed them. The feeding process is fairly slow when compared to adult eating.
They can only be fed in one of following ways:
- Breastfeeding from any lactating pawn, even those not their mother.
- Cooking and feeding them baby food, produced at a campfire or stove from vegetable ingredients.
- Feeding them animal milk or insect jelly.
Of these, breastfeeding is usually the easiest. Unlike other foods, which feed in bursts only once the food has been consumed, breastfeeding will gradually increase the food bar. This allows the breastfeeding pawn to pause at any point, whilst also not wasting excess food. Usually, a pawn will sit down to breastfeed, continuing until the baby is full or the pawn is out of milk.
You can control what foods the baby can eat and who will try to feed the baby in the baby's "Feeding" tab. By default, the mother will be set to Urgent, with all other pawns set to Childcare. If a pawn is set to childcare, that does not mean they will feed the baby: their childcare labor may be turned off, or they may be incapable of it.
- "Urgent" means the pawn will feed the baby day or night, even if the pawn is not assigned to childcare or capable of it.
- "Childcare" means the pawn will feed the baby as childcare work.
- "Never" means the pawn won't automatically feed the baby.
You can allow the baby to eat milk, insect jelly, and baby food in this tab, but can't control breastfeeding here.
Although babies are limited to eating certain foods, you can administer drugs to babies under the Health>>Medical Operations tab. These have an outsized influence due to their very small body sizes (x0.20 of the size of an adult). Each drug causes a higher severity, increasing its duration. But due to the massive tolerance, any further drugs are very likely to get them addicted. The actual effects of a drug are the same between babies and adults.
Unlike adults, babies don't follow a sleep schedule, instead falling asleep mostly at random. They may be in a sleeping spot, growing steadily more sleepy and upset, while still not falling asleep.
A crib or bed should be provided for the baby to sleep in, as it will negate the negative mood from sleeping on the floor. There are several benefits of cribs over beds: cribs take up only one tile, multiple can be placed in a room without turning it into a barracks, and high-quality cribs can increase the mood of the baby while it rests or sleeps.
Force-feeding, holding, or playing with the baby will wake them up, possibly keeping them unhappy from being tired.
Babies need to be played with, in place of standard Recreation. An adult assigned to child care will play with the baby once the play need is almost empty. There are different activities that will fulfill the baby's play need. A toy box and baby decoration increases the quality of play.
Babies' moods are influenced by their needs for food, sleep, and play. These are affected at the same rates as for adults:
|Play||Really wants to play||Wants to Play||Normal||Entertained||Very Entertained|
Babies share some moodlets with adults but aren't affected by as many thoughts. Babies can gain the −4 Slept in the Cold moodlet, but aren't affected by temperature while awake. Babies have the same expectations for colony life as other pawns do, influencing their moods at the same rate. They can be influenced by psychic drones, soothes, and psycasts just as much as other pawns, because they have a psychic sensitivity of 100% by default. However, babies don't consider furniture comfort or quality, except while resting or sleeping in a crib, with various crib qualities providing higher mood boosts.
Uniquely, babies get a mood bonus when their parents are very happy: "Parent is happy" +6, or "Parents are happy" +12.
Being held or breastfed does not affect the baby or caretaking adult's mood in any direct way. However, babies will temporarily forget any ill mood effects from lack of Sleep while being held, although these needs will still decrease as usual.
A baby's mood affects the moods of all other colonists, much like children's moods can. Parents of a baby who is very happy will receive a +6 mood boost for "My child <baby> is happy". If the baby is about 1/3 of its happiness or less, parents have a −6 mood penalty, thinking "My child <baby> is unhappy". Babies also factor into the colonists' thoughts on the overall happiness of the colony's children, which range from a positive +2 "Happy youngsters" mood boost to a −2 "Sad youngsters", to worse negative mood penalties, all based on the average of the moods of colonists aged 0-17.
Giggling and crying
Instead of mental inspirations or mental breaks, babies will have giggling or crying "fits" which gives a mood boost or penalty to other colonists within a 10 tile radius. The ratio between giggling and crying is directly related with the baby's mood.
Mood boosts from giggling babies go from +4 up to +10, while crying babies can cause mood maluses from −8 down to −20. Parents are only half as bothered by their baby crying, and twice as happy when their baby is giggling.
|Giggling to crying ratio (higher is better)|
Babies get the same social opinion boosts from familial relationships that other pawns do. They are born aware of their entire family tree, going back to the great-grandparent generation and including dead relatives. In addition, their social relationships are impacted by who feeds them and who hears them crying. They will not know all of your colonists when born, only beginning to remember them after they've interacted a few times (and the colonist will likewise not remember the baby)!
Feeding changes the social opinions between a baby and their caretaker. A baby will gain about +16 social opinion for another pawn each time they are fed, with the "Fed me" opinion, which wears off over time. It is unclear whether breastfeeding provides a similar benefit. An adult who feeds a baby will gain about +4 social opinion for them from this act, and remember the feeding for longer than the baby does. This bonus only stacks up to 5 times, for a maximum of +16 opinion of the baby. Adults who breastfeed a baby gain about +7 opinion for the baby from the interaction. These feeding opinion changes are the same whether the caretaker is the baby's parent or not.
Adults who hear a baby cry or giggle will change their opinions of the baby temporarily. A crying baby will gain the Cried −12 opinion penalty, while a giggling baby will gain the Giggled +12 opinion boost. An adult can remember a baby's crying and giggling at the same time, cancelling each effect out. It is unclear if these modifiers stack.
- Biotech DLC release - Introduced. Humans have a gestation cycle defined without Biotech, but they can not get pregnant.
- 1.4.3555 - Lactating pawns are now able to become pregnant and have ovums extracted, but have a x5% multiplier to Fertility. Terminate pregnancy operation increased to 2 medicine (from 1), work slightly reduced.