When The Sims 4 introduced infants, it added one of the most detailed—and frustrating—life stages the game has ever seen. With 35 possible infant milestones in a long lifespan, many players are discovering (often years later) that they’ve never seen half of them.
Originally shared on Reddit two years ago, the post recently resurfaced and sparked a massive discussion among Simmers who suddenly realized, “Oh… that’s why I never get first word.”
Reposting this 2 years later in case anybody hasn't seen it yet! Infant milestones – 35 – long lifespan
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Let’s break down what players have learned through experience, testing, and a little bit of suffering.
Why Infant Milestones Feel So Hard to Complete
Infants are extremely time-sensitive, especially with normal or long lifespans. Many milestones are tied to specific actions that must occur before a skill level is too high—or sometimes before the infant ages up at all.
Several players admitted they:
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Turned aging off and still couldn’t unlock everything
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Missed milestones without realizing they existed
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Didn’t know certain “life event” milestones were even a thing
In short: the system is unintuitive, and the game doesn’t explain itself well.
Every infant milestone in The Sims 4, laid out by category—from fine motor and gross motor skills to social moments, firsts, and life events most players never unlock.
Lifespan Matters More Than You Think
One of the most useful community discoveries is that a short lifespan actually makes milestones easier.
“It’s easier to get milestones on short lifespan because they trigger faster.”
Switching to a short lifespan temporarily while actively working on milestones can dramatically improve success rates. Many players now toggle lifespans strategically instead of sticking to one setting.
Social Milestones: First Word Is the Big Mystery
The First Word milestone is one of the most commonly missed—and most discussed.
What seems to trigger it based on player experience:
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Adults frequently talking to the infant
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Reading bedtime stories
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Social interactions happening around the infant
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Older siblings entertaining or chatting with them
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The infant autonomously approaching caregivers
Notably, players report not needing to actively train this milestone. In many cases, it triggers organically when social interaction is constant.
Meanwhile, others struggle to unlock even half of the social category, especially on longer lifespans.
Gross Motor & Fine Motor Pitfalls
Some milestones are easy to accidentally lock yourself out of.
For example:
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If thinking skill levels up too fast before completing “shapes into numbers,” you may miss the milestone.
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Similar issues happen with crawling, running around, and other motor milestones
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In some cases, players have to roll back skills or cheat milestones if they progress “too efficiently.”
This has led many to call the system partially broken—because progressing too efficiently can actually punish you.
Learn to Dance (Yes, That’s a Thing)
Many players didn’t even know infants could learn to dance.
How players unlocked it:
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Actively placing a speaker near the infant
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Encouraging wiggling and listening to music
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Repeating music interactions frequently
For some, this milestone never appears at all—leading others to jokingly call it a “flex” when unlocked, especially with twins.
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Life Event Milestones: Chaos Required
Some infant milestones are tied to… questionable life experiences.
Confirmed or reported milestones include:
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First vacation
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First park visit
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First fire (yes, really)
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Surviving a fire
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First burglar (added later via updates)
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Haunted house survival (seven days!)
Unsurprisingly, many players find these unrealistic or outright ridiculous.
“What INFANT needs to go through that?”
Thankfully, these are not required to earn the Top-Notch Infant trait, despite common fears.
Top-Notch Infant: What Actually Matters
You do not need every milestone.
Players report earning Top-Notch Infant with:
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Partial social, gross motor, and fine motor completion
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High needs being consistently met
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Regular care and interaction
Letting infants get tired or hungry too often may interfere with the trait, even if milestones are otherwise progressing well.
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Bugs, Glitches, and… Diaper Blowouts
Like most Sims systems, infants aren’t bug-free.
Community notes include:
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Milestones failing to trigger properly
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Needing cheats if milestones were skipped unintentionally
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Diaper blowouts triggering frequently
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The “peed on caregiver” milestone appearing more often when using a changing table
And yes—some players have experienced these milestones both in-game and in real life.
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Final Thoughts: Why Players Are Still Talking About This
Two years later, players are still discovering infant milestones they’ve never seen. That alone says a lot.
Infants in The Sims 4 are:
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Impressively realistic
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Deeply detailed
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Poorly explained
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Sometimes unintentionally punishing
Yet for many Simmers, that challenge is part of the appeal. Whether you’re a legacy player, a completionist, or someone just trying to survive twin infants, understanding how these milestones work can make the stage far more enjoyable—and far less stressful.
Every tiny movement matters. In The Sims 4, infant milestones like crawling, first words, and motor skills often unlock through everyday interactions—sometimes when you least expect it.
If nothing else, remember this: you’re not bad at the game—you were just never told how it worked.
Source: Reddit
