As we consider whether to add a third child to our family, a big consideration that has come up is when to have the baby. While some of the considerations are financial or career-related, we also have considered what sibling spacing would be ideal. I think it’s fair to say that we found the 18-month age gap to be perfect for us and for the individual personalities of our kids.

I’ve read up quite a bit on the pros and cons of different sibling spacing, including effects on children as well as maternal health. Although much of the research and anecdotal evidence seems to favor a three-year age gap over any other, Mr. Dolphin and I were really hoping for Irish twins. We ended up with the two boys being 18-months apart and I was prepared for life with two-under-two to be really difficult. We were pleasantly surprised and in all honesty found life easier after Panda joined our family. To be fair, our situation may be difficult to replicate because Panda was the world’s easiest baby who slept non-stop for the first two months of his life and rarely cried. Additionally, Lion was a very needy baby, but when Panda came along, seemed to have some of his needs fulfilled simply by virtue of having (and being) a brother.


They LOVE dressing alike, it’s not us encouraging it, I swear!

As the kids grow a little older, I am even more in love with the 18-month age gap, though I see positives in a larger gap, as well (which is good since, if we do have a third, the age gap is likely to be more like three years between our two younger ones). Here are our pros and cons for an 18-month gap.



  • Sibling bonding. While there is no guarantee that a closer age gap will promote a good sibling relationship, we felt that having kids closer in age would mean that they would be able to play together more and have the same interests for a longer period. Time will tell how long they remain close, but since we brought Panda home from the hospital the two have been practically inseparable. Lion adores Panda, cares about his well-being, is always looking after him, and wants to play with him. Panda, of course, is smitten with his older brother and basks in the attention from Lion. For us, this was the absolute best part of a small age gap and a big reason why we wanted them to be close in age. I was ten years older than my brother and even today, as grown adults, I feel like it can be hard to relate because we’re still in different places in our lives.
  • Ability to enjoy the same activities. This one piggybacks on the above, but it’s more about how convenient it is for us to be able to set them in front of the Duplos and know that they’ll both enjoy building with them, or reading board books together because Lion hasn’t totally grown out of them yet. I hope that as they grow older, they’ll continue enjoying the same activities and help reduce the number of places/things we need to do.
  • Fewer years of separate drop-offs. Because they’re close in age, for quite a few years, they’ll overlap at the same schools. The convenience of a single drop-off (from a person currently doing two different daycares!) cannot be overstated in my mind.
  • Still in baby mode. I’m glad we never got out of “baby mode” with Lion when we had Panda. Lion was still in diapers, still wanting to be carried around and still hit-or-miss on sleeping through the night. I feel like because we were still in baby mode, it didn’t feel like we were starting over.
  • Shorter period of parenting responsibility. I’m not sure that this one is articulated well, but if Lion and Panda are our only children, we will only be responsible for the kids for 19.5 years (more like 20 based on Panda’s birthday and high school graduation). While, of course, parents are parents forever, I like that after 20 total years of parenting both kids (absent a third), they’ll be out of the house.
  • Quick turnaround for hand-me-downs. Another pro to the closer age gap is that we don’t have to store hand-me-downs for as long. Although we did have to buy some new clothes for Panda because they were born in opposite seasons, as they grow older, this won’t be as necessary and he can inherit much of his brother’s clothes. One year of storage and the clothes will be ready to pass down.
  • No memory of life pre-second child. Lion clearly has no memory of life before Panda, which I think helps reduce sibling rivalry or resentment.


One of their favorite things to do in the mornings is ask to get into the other’s crib. 


  • Lack of independence. While I think Lion became more independent after we had Panda, the fact that he was just 18-months-old meant that he still needed us to do a lot for him. Having two kids that dependent on us was sometimes difficult.
  • Inability to hand-down everything. If the sibling spacing were farther apart, we might have been able to pass down the crib, high chair/booster seat, and car seat. While we did consider trying to move Lion into a toddler bed before Panda arrived, we ended up getting a mattress for our pack-n-play and used that as a second crib. As a result, we did have to buy a lot of second baby equipment.
  • Possible need for a second/double stroller. I actually question whether we “need” a second/double stroller. While we do use it with some frequency, we went many months with just a single stroller and baby-wearing or a single stroller while Lion walked. If Lion was older, I wouldn’t have thought twice about getting a second stroller or a double stroller and instead would have opted for a ride-along board or just expected Lion to walk.
  • Expenses. Oh my gosh, this was the hardest part of this age gap for us. Two children in diapers plus childcare costs really stretched our budget last year and, to be totally truthful, put us in a little bit of a hole until I got a raise. In our area, daycares are really expensive for the first two years, but some drop down in price either at age 2 or 3 (often dramatically). We ended up having to pay the infant/toddler rate for two kids at the same time. Although we got a break when Lion turned 2, having two kids in daycare full time is still really tough. Another mom commented that we’d end up paying the same amount no matter what and it’s just really concentrated. While that perspective does help, at the end of the day, we don’t have endless income so that price tag really does hurt.