Developmental Milestones

The Only 6-Month Milestones That Matter

Most parents overdo the whole milestone thing in the sixth month. Stop stressing out and focus on the two (just two!) developmental moments that really matter.

Originally Published: 
Baby looking over her mother's shoulder.

If you haven’t spent the first months of your child’s life focused on baby developmental milestones, reaching the half-year mark will likely put them front of mind. Though hitting the midway point of the first year is a big moment for parents, 6-month milestones tend to be broad changes since babies are within range of a few overlapping developmental milestones — but nothing about human development is pegged to a particular day on the calendar.

Many parents think of milestones sequentially, with one skill giving way to the next, on schedule, as kids get older. But in reality, each baby is a complex and unique individual that develops at their own pace. They hit milestones at different moments and in different sequences. There might be a “typical” skill set for 6-month-olds, but no baby will be exactly as described in baby books and on parenting sites, and that’s okay.

The most useful 6-month milestones use global behaviors and traits as metrics, rather than a set of specific skills. Keep in mind that you’ve got six months of experience with the growth of your child. If something seems off, it probably is. But if you feel your baby is progressing at the clip they’ve been at for the previous months, then everything is likely fine.

To help parents track how their child is developing, the Centers for Disease Control and Prevention (CDC) and the American Academy of Pediatrics overhauled the pediatric milestone checklist in February 2022, This process included adding developmental milestones for 15-month-olds and 30-month-olds, and revamping other milestone charts to reflect things most children (75% or more) can do by a certain age. To help parents track milestones on their own, the CDC has released a free Milestone Tracker mobile app, a Digital Online Checklist, and a PDF checklist that parents can download and print. But here are the two milestones for 6-month-olds that stand out above the rest.

6-Month-Old Baby Milestone #1: Baby Gets Seriously Curious

More than any little thing that parents are told to look for at 6 months, they will want to see a general inclination toward curiosity. How do you know if your baby is curious? If you find yourself asking your baby questions like, “What was that? What is that? Did you hear that? Do you see that?” it’s very likely that you are responding to your baby’s curiosity cues.

Your baby may look around if they hear a new sound, or stare intently at a new sight or new person. They might reach out and bat at a new object. They might chew on toys and turn them over in their hands. They will splash in liquids and drop objects. All of these are signs of curiosity.

This curiosity feeds off of itself, and its presence means that body systems are integrating and working together. A 6-month-old’s curiosity means that they are beginning to recognize what’s novel and what’s familiar. The ability to explore objects with hands and mouth shows that muscles are developing correctly and that your baby is developing dexterity. Reaching for objects or listening intently to new sounds shows that a child’s hearing and sight are coming along as well.

Red Flags: You’ll want to talk to your pediatrician if your baby isn’t showing at least some pointed curiosity in their day-to-day life. That’s particularly true if the lack of curiosity is paired with listlessness or a disinterest in parents.

What You Shouldn’t Stress About: If your baby is a bit quiet or slow to explore their surroundings, that’s not a huge concern as long as they’re showing some inclination toward curiosity. Place your baby’s behavior in the context of the previous months. If they’ve always been slow to react and explore, it’s likely a product of their particular temperament rather than a developmental delay. Still, any concerns should be brought to a pediatrician.

6-Month-Old Baby Milestone #2: Baby Is Making Moves

At the 6-month mark, some babies have actually started to master movement (time to get on baby-proofing your home!). A small number of babies in the 6-month range can actually get on their hands and knees and crawl. But although some babies can crawl, many others aren’t ready to. Some babies will skip crawling altogether for butt scooting, rolling, scuttling, tripod walking, or dragging. If it works to get them where they want to go, it honestly doesn’t matter which they do.

At 6 months, many babies will have developed the core strength to hold themselves in a quasi-seated position, using their hands to prop themselves up. When on their belly, some babies have figured out how to roll over. Others can kick themselves forward toward an object they find interesting.

The upshot is that a 6-month-old should be a physically active creature and relatively purposeful in their activity.

Red Flags: At 6 months, babies should have a pretty strong core and the ability to coordinate their limbs around a task. Parents should tell their pediatrician if their baby seems particularly floppy, or seems unable or unwilling to move, turn their head, or coordinate their limbs.

What You Shouldn’t Stress About: Don’t worry about crawling specifically — this isn’t the end-all goal for your soon-to-be bipedal kid. Some babies crawl, some babies don’t. Some babies go from rolling over to cruising to walking. You don’t need to spend an inordinate amount of time getting your baby to crawl. Just give them opportunities to explore their world.

Non-Milestone Moments in Baby’s Sixth Month

Around 6 months of age, you’ll hear and read a lot about your baby’s ability to recognize object permanence. That’s the concept that objects and people don’t just disappear when they are out of sight. But there is some controversy as to whether babies are starting to understand object permanence at 6 months or if they’re just developing the ability to show that they already understood the concept.

This article was originally published on