How do you have twins in The Sims 4?
Sims 4 twins and baby gender: how to have twins, and do carrots make a boy?
A pregnancy in The Sims 4 gives twins 10% of the time and triplets 1%. The Fertile trait raises twins to 20%, and a home lot with the On Ley Line trait to 84.1%. Carrots really make boys: one in the first trimester moves the odds 25 points, so two make a boy certain (100%).
Two hidden numbers decide a Sims 4 baby: how many babies, and boy or girl. Both are rolled when the baby is born, from tuning you can push in your favour.
The number of babies is a weighted roll. A human pregnancy weighs 89 for one baby, 10 for twins and 1 for triplets, so twins come 10% of the time and triplets 1%. Fertility items work by shrinking the weight of one baby, never by raising twins directly.
- 10%Twins, with no boost
- 1%Triplets, with no boost
- 84.1%Twins on an On Ley Line home lot
Twin and triplet odds by boost
| Situation | One baby | Twins | Triplets |
|---|---|---|---|
| No boost | 89% | 10% | 1% |
| Fertile trait | 78% | 20% | 2% |
| Fertility Massage (Spa Day) | 66.9% | 30.1% | 3% |
| Fertility Massage with incense | 54.8% | 41.1% | 4.1% |
| Masterwork Elixir of Fertility | 32.7% | 61.2% | 6.1% |
| On Ley Line home lot | 7.5% | 84.1% | 8.4% |
| Fertile on an On Ley Line lot | 3.4% | 87.8% | 8.8% |
Every multiplier on the weight of one baby
| Boost | Multiplier | Pack |
|---|---|---|
| Fertile trait | ×0.44 | Base game |
| Elixir of Fertility | ×0.5 | Outdoor Retreat |
| Elixir of Fertility, normal quality | ×0.25 | Outdoor Retreat |
| Elixir of Fertility, outstanding quality | ×0.13 | Outdoor Retreat |
| Elixir of Fertility, masterwork quality | ×0.06 | Outdoor Retreat |
| Fertility Boost (Fertility Massage) | ×0.25 | Spa Day |
| Fertility Boost (Fertility Massage with incense) | ×0.15 | Spa Day |
| On Ley Line lot trait (home lot) | ×0.01 | City Living |
| Breeding Ground lot trait (cats and dogs) | ×0 | Cats & Dogs |
| Fertility Unleashed | ×0.25 | Businesses & Hobbies |
| Baby Boom decree | ×0.25 | Royalty & Legacy |
Each baby after the first has a 33.33% chance to be an identical copy of the one before. Cats and dogs: one baby 24.9%, twins 50.3%, triplets 24.9%. Horses always have one foal.
Boy or girl: carrots and strawberries
| Trimester | One carrot (toward a boy) | One strawberry (toward a girl) | Chance of a boy after two carrots |
|---|---|---|---|
| 1st | -25 | +25 | 100% |
| 2nd | -16.67 | +16.67 | 83.3% |
| 3rd | -10 | +10 | 70% |
The radio counts too: Alternative nudges toward a boy, Pop nudges toward a girl. See the 1st trimester moodlet and how to have a baby.
How to have twins
The strongest boost is where you live. If the pregnant Sim's home lot has the On Ley Line lot trait from City Living, the weight of a single baby is multiplied by 0.01. Twins then come 84.1% of the time and triplets 8.4%.
The Fertile trait multiplies the single weight by 0.4382, which makes twins 20%. A Fertility Massage from Spa Day gives Fertility Boost, which makes twins 30.1%, or 41.1% with incense. A masterwork Elixir of Fertility from Outdoor Retreat makes twins 61.2%. Boosts stack: Fertile on an On Ley Line lot makes twins 87.8%.
Triplets can't pass about 9.1% for humans, because only the single weight shrinks: the 10 for twins and the 1 for triplets stay. The game also caps the babies at the free spaces in your household plus one.
Do carrots make a boy? Yes
A pregnant Sim has a hidden gender chance from 0 to 100. It starts at 50. At birth the chance of a girl is the value out of 100, so 0 means a certain boy and 100 a certain girl.
Eating a carrot from the garden moves it 25 points toward a boy in the first trimester. So two carrots in the first trimester make a boy certain. Strawberries do the same toward a girl. Later carrots move it less, so start early.
Music counts too, in small steps: the Alternative radio station nudges toward a boy, and Pop toward a girl.
Identical twins, pets and horses
After the first baby, each extra baby has a 33.33% chance to copy the one before it: same sex and same genes, so identical twins.
Cats and dogs have their own odds. Their twin weight is multiplied by 18 and their triplet weight by 89, so a litter is a single puppy or kitten only 24.9% of the time. Horses always have one foal.
Questions
How many carrots do you need for a boy in The Sims 4?
Two, eaten in the first trimester. Each one moves the hidden gender chance from 50 toward 0 by 25 points, and at 0 the baby is a boy for certain. One carrot in the first trimester makes a boy 75% likely.
Does the On Ley Line lot trait give twins?
Almost always. On a home lot with On Ley Line, the weight of a single baby is multiplied by 0.01, so twins come 84.1% of the time, triplets 8.4% and one baby only 7.5%.
Does the Fertile trait increase twins in The Sims 4?
Yes. Fertile multiplies the weight of a single baby by 0.4382, which doubles the odds of twins from 10% to 20% and triplets from 1% to 2%.