There's something about holding someone else's baby that makes people ask you if and when you're having a child of your own. And if you already have a kid, they want to know when you'll be having another.

I encountered this after my dear friend gave birth to her firstborn, a boy. I had joined her family in a crowded hospital room, where we stood in a half-circle around her bed and passed the baby around. When the little bundle reached me, I cradled him in my arms. As I enjoyed the warmth of a sleeping child only a few hours old, my friend's brother-in-law asked if I had any children.

"One daughter, she's 3," I replied.

"Oh, you'll want more," the man said.

"We're happy with one," I reassured him.

"You'll change your mind," he said.

I wasn't about to get into an argument in a small hospital room during one of the happiest days of my friend's life. So I just smiled, passed the baby on to the next pair of outreached hands, and kept the visit short. I didn't have time to explain that I was content as we were, and that, instead of having more children, I wanted to travel.

It's often assumed that children benefit from having siblings, as if a sibling offers the firstborn an instant playmate, a guaranteed best friend, a confidante. From the time my daughter was outgrowing diapers to the day she started kindergarten, I was asked by everyone from my mother to my neighbors to random coworkers when Number Two would make his or her debut. Sometimes, even my own daughter would ask why we never gave her a brother or sister.

There were many reasons. One is that I knew firsthand that it's not a guarantee that siblings will get along or grow to be close. My brother and I are two-and-a-half years apart, and we're not close at all — I can't recall the last time we spoke on the phone. My mother-in-law and her sister were 11 months apart, and bickered nonstop until my mother-in-law's death at age 64.

The other reason is because, well, kids are expensive. Take the basics of food, health care, and education out of the equation and you still have sports practice, art class, birthday parties, sleepovers, movie tickets, summer camp, and — oh my God — orthodontics.

My mother grew up poor, the oldest of four children; she and one sister are just 13 months apart while there is an almost 15-year gap between her and her other sister. My brother and I grew up in a financially-strapped household, and when my mother asked when I was having a second child, I told her I didn't want to live hand-to-mouth anymore. "You manage," she said. But I didn't want to merely "manage." I wanted to explore, and exploring costs money.

The basic question boiled down to: Could I afford to live the way I wanted to live with more than one child?

The answer was emphatically no.

My family and I live in the suburbs of New York City, one of the most expensive regions of America. It's not an area we necessarily like — it's filled with workaholic stress junkies who overschedule their children with every imaginable activity, from violin lessons to computer coding camp. But we're anchored here by our jobs. Back in 2008 and 2009, when I was still in my late 30s earning a $72,000 annual salary from an office job, we paid approximately $13,000 a year in daycare. As I pondered the idea of a second child, I remember thinking that the additional daycare costs could pay for at least three family trips to the Caribbean — and at a nice hotel. We could even try different islands! Could we afford to fly a family of four to all the numerous places I so badly wanted to see?

We kept a large map of the world posted on a wall in a spare room, countries and cities we had visited marked with little stickers my daughter had placed. Alone, I would stare at this map, drag my finger to the Faroe Islands, the Seychelles Islands, try and find French Polynesia again because I always forgot where exactly it was in that big swath of blue. The truth was, I was more drawn to this map than my friend's baby.

I remember thinking if I said this out loud to anyone, someone would tell me I was being selfish, depriving my daughter the sacrosanct sibling relationship, putting my own interests before those of my family. But I grew increasingly comfortable with this one selfish ambition. I had traveled before motherhood, and I wanted to keep traveling. This felt very natural to me, no matter what other people said. Women are constantly pressured into roles they may not be ready for: wife, mother, household guru. We're told to travel the world before "settling down," not pack up the kid and jet-set the globe. But over time, I've learned that being maternal doesn't always mean being domestic.

I looked around at other parents at our daughter's daycare who had at least two children and took some mental notes. Parents of two (or more) are always short on two things: time and money. Even weekends were all-consuming: One parent would cheer at the eldest's dance recital while the other parent drove the youngest to soccer practice. And international travel was almost unheard of. Family vacations were long weekends at the Jersey Shore, which is absolutely fine, but not for me.

We stuck with one child, completely comfortable as a family of three, never feeling that tug to add one more. My husband and I are blessed with a healthy, beautiful girl who got her first passport at age 2 and, now at 13, has been to nine countries on four continents. I love being a mom. My daughter is the sun in my sky, and her wellbeing is my top priority. But I also love to travel. It's a part of who I am, and now it's becoming part of my daughter.

A month after the encounter in the hospital room with my friend's brother-in-law, me, my husband, and our daughter went on a trip to the Galapagos Islands where my daughter served as the flower girl in a wedding. It would become an unforgettable nine-day trip of island hopping, lost luggage, handwashing underwear in hotel sinks, beautiful undeveloped beaches, delicious homemade guava jam, and amazing wildlife. It was life-changing, and we haven't stopped globetrotting. We maintain an address and take trips when the school calendar allows. We don't get to go everywhere, and we won't get to see everything, but we do get to see and do quite a lot. I fully embraced motherhood, from midnight breastfeeding to watching my daughter stamp off stage during her dance recital to frosting her pink birthday cakes to taking her bra shopping. And at the same time, I relish the freedom we have to explore this extraordinary Earth.