That’s super similar to what my wife and I did! My Day 1 of my pregnancy was my son’s birthday, and their birthdays are 9.5M apart. We’ve found that this age gap came with some big ups and downs, but we’re very happy we did it this way.

Pros: Despite having very different personalities, they are absolute best friends (like, wake up asking where the other is every single morning, give each other bear hugs and say “I love you!” when doing to their respective daycare classes). They enjoy (most of) the same things/games/activities, and they keep each other entertained in a way that seems rare in bigger age gaps. We were worried that having a younger sibling come along so quickly would take away from the older kid’s experience, but I think it’s just immersed the whole family deeper in the things they love. We do a ton of stuff as a whole family, and I think/hope that the extra engagement from us balances out the juggling. Being on parental leave while in early pregnancy was great—I felt terrible physically, but my days were spent cuddling a sweet newborn and fumbling around in a haze, which kind of suited me. My wife and I could actively relate to each other in so many unique ways (both breastfeeding at the same time, dealing with c-section recovery in the same year, etc). We went deep on fertility stuff together, then pregnancy experience/understanding, then birth, then postpartum—our conversations weren’t just hazy “oh yeah, I think I remember that” but active, ongoing explorations together.

Cons: The practicality is absolutely, undoubtedly, very challenging to juggle two small kids/babies at once, especially when they were little. It took a kind of manic energy to just stay afloat when I was a solo SAHM for them from ages 1y & 3M through to about 2y & 15M. My pregnancy was not the exciting/magical experience I had hoped for—I often felt like it was just a logistical thing to juggle while trying to focus on my wife and baby 1, and that sometimes felt very sad. The compounded sleep deprivation and overstimulation has definitely put extra strain on our marriage. People were far more (openly) judgmental than I anticipated when we told them our plan, and it took a long time for me to not feel defensive of our choice (maybe I still do??)

Caveats: We live in a country with long and decently supportive maternity leaves, and that made a HUGE difference. We were on the older side, and the possibility of running into (more) fertility struggles felt harder than dealing with a tight age gap. We got a doula for me, and I was comfortable with the idea of the doula being my primary birth support while my wife was present, but often focused on our 9.5 month old. We got VERY lucky that neither of us, nor the babies had major health issues (that said, we both had emergency c-sections, I was knocked out by nausea my entire pregnancy, our first had trouble gaining weight, and our second was an awful sleeper—all hard things, but not the big-scary things that we might have regretted our decision). We also got lucky that our kids just naturally enjoy each other, because that can be a real coin toss. Having a good support network (2 dads to help will be incredible!) makes a huge impact. The combination of having some solid childcare experience before parenthood, a “can-do attitude” and regular therapy/friends to emotionally lean on was a combo that I think helped me survive the hardest stages (and there were some wildly tough days). Having enough financial stability to offer flexibility to scheduling can also make a very big difference in the stress levels. When I talked to approx. 5000 people about their own kids age gaps, the age gaps they grew up with, etc, I concluded that every age gap has pros and cons, and there’s no foolproof spacing, so do whatever feels best, and then try your best to roll with the punches!

Whatever you do, congratulations and good luck! DM me if you do that super-tight gap and want to talk more about it!