What’s the Best Age Gap Between Kids? Well, That Depends

So you know you want another (baby, that is) and now you’re wondering about the best age gap between kids. Well, friends, there’s really no right or wrong answer when it comes to deciding when to bring another child into the world—namely because there are numerous personal factors to consider. (What does your family look like now? What priorities do you and your partner share? What about your economic circumstances?) That said, we suggest you read on for some guidance that can help you put things into perspective and approach family planning with confidence.

The short answer to the question at hand is yes, the age gap between siblings does matter. Meri Wallace, LCSW, writes in Psychology Today that “large and small age gaps strongly affect children’s experiences…[and] can affect how siblings feel about each other.” Indeed, there are costs and benefits to both—but, regardless of the interval you choose for your family, the expert says that a little foresight can go a long way towards helping you mitigate the age gap challenges that arise. Here, a breakdown of the pros and cons of the various birth spacing intervals you might be considering.

“I think the cons are most evident when they’re really little—having two kids that you have to carry and that are still in diapers is no picnic. And my under-two son was pretty confused by and jealous of his sister when she arrived. But I’m more appreciative of their close gap as they age. Now that they’re elementary school-aged and one grade apart, they are truly each other’s best friends. And because they’re into the same things, it’s easy to make plans, pick movies for the whole family and even think about vacations. Sometimes the closeness can feel a little oppressive, but overall I love that they’re so on the same page with how they think and what they want to do. (And it was pretty great to get all the diapers done with in one fell swoop.)” —Jill, NY

Pros:

• You’ll have the hardest part of building a family behind you faster, as a small age gap condenses the most fatiguing years of parenthood (i.e., pregnancy and the early years).
• Siblings who are very close in age are more likely to share similar interests and play together.
• A smaller age gap means kids will be working on the same skills in close succession, allowing the older sibling to assume a positive teaching role. (Showing the baby how to stack blocks, for example.)
• You’ll benefit from the fact that all the basics of infant care—swaddling, feeding and bathing, to name a few—are still relatively fresh.

Cons:

• According to a 2005 meta-analysis published in the International Journal of Gynecology and Obstetrics, there is an increased risk of adverse birth outcomes when the interpregnancy interval is less than 18 months.
• Siblings who are close in age are more likely to experience jealousy and sibling rivalry as they might feel they are competing for similar resources. And yes, this is true even if the older sibling is very little—a 2008 York University research study revealed that babies as young as three months can feel jealousy.
• The demands of pregnancy, birth and the newborn phase are no picnic at any time, but the job is particularly grueling when you’ve also got a toddler on your hands.
• A small age gap can be more costly, since it’s less likely the older sibling will have outgrown certain big-ticket items (think: stroller, highchair, and crib).

“My kids are 27 months apart and in the beginning it was a little challenging, both emotionally and physically. My daughter loved her little brother from the start and was very sweet with him, but definitely also had moments of resenting how needy he was—like when he’d nap for only 15 minutes and wake up as soon as I sat down to play with her. (Enter, mom guilt.) Still, I think it was a lot easier to reassure her because she was already speaking a ton and was more or less able to understand what was going on. (Also, it was pretty great that I only had two kids in diapers for one or two months, max.) Now my youngest is almost 5 and my daughter is 7, and I think the age gap is great. They’re absolutely best friends—sometimes partners in crime—and play together all the time. There’s bickering, of course, but their bond is incredibly strong and it’s super sweet to witness in action.” —Sara, CT

Pros:

• Per the American College of Obstetrics and Gynecology College, this age gap is the least likely to result in adverse outcomes for mother and baby.
• You’ll benefit from having given your body a chance to recover from your last birth and catch up on sleep—assuming your first (or youngest) child is on a regular schedule, that is.
• You will likely be able to save money by reusing all the baby gear that your last child has outgrown, but you haven’t yet parted with.
• This age gap is the most popular one, which means your children won’t have too much trouble finding similarly-aged sibling pairs to befriend.
• Kids will be able to play together and enjoy a close relationship after a couple of years.

Cons:

• As previously mentioned, one plus is that the sibling relationship will likely blossom once the new baby reaches two or three years of age. The downside? You’ll have to survive the baby years with a disinterested and demanding 2-year-old or threenager in tow before you reach that promised land.
• Your oldest may regress. It’s common for kids to regress after the birth of a sibling (hello, potty training accidents, thumb-sucking and baby talk), but this is especially common behavior with toddlers. 

“I have a 10-year-old, 5-year-old and 3-year-old and my oldest is absolutely my little helper! He’s so mature and thoughtful—always looking out for his two younger siblings and they just adore him. We live in California and I recently had to evacuate our home with the three kids and our dog and I don’t know how I would’ve gotten us all into the car and into safety without him. I also loved the age gap between him and my middle child because it meant that I only ever had to pay for childcare for one kid since my oldest was in the public school system by the time she came along. (Then my youngest was born and that’s sadly no longer the case!)” —Lauren, CA

Pros:

• You can avoid the parenting burnout that can result from caring for more than one small child at the same time.
• The older sibling will be of school age, which gives you more undivided time to care for and bond with your newborn.
• Slightly older children are less likely to feel jealous of or inclined to compete with their new sibling.
• A larger age gap means that the older sibling is in a better position to assume a helping role when the baby is born (and you need all hands on deck).

Cons:

• Research shows that a large age gap could result in a riskier pregnancy. A 2020 study published in the American Journal of Obstetrics and Gynecology MFM indicates that long interpregnancy intervals of 60 months or more are associated with higher rates of cesarean delivery, while another study published in Science China suggests a link between long interpregnancy intervals and adverse perinatal outcomes, including preterm birth.
• Your memory might be a little rusty when it comes to the early years of parenting. (Don’t worry, your newborn will give you a sink-or-swim refresher course, we promise.)
• A large age gap between kids generally means they will not have similar interests or be eager to play together, so the sibling bond will probably not reach its full potential until they’re considerably older.