I wondered if my three girls, two identical, one fraternal, would lose their individual identities. I needn't have worried.

Puppy, Stinky Puppy and Other Puppy used to be white and fluffy plush dogs about the size of guinea pigs. They arrived at the hospital in small gift bags the day after I gave birth to my triplets, a set of girls, two identical, one fraternal. The identical pair, Ainsley and Patten, adopted all three of the stuffed dogs, snuggling in their soft fur and playing with their nubby tails. My fraternal girl, Gwen, opted for a small, pink bunny with a blankie attached.

Over time, Ainsley and Patten loved the dogs’ bright, soft fur into gray, matted messes, the dogs becoming bath-soaked versions of themselves. To anyone else, Puppy, Stinky Puppy and Other Puppy all looked the same, save Stinky Puppy’s one dark paw that Ainsley had sucked to a flat, stinky knob. Yet, to my identical girls, their “mommies,” the puppies were distinct enough to spot from across the room.

I think about my children’s lovies often. They have become symbols of the triplets who love them, leaving me with more questions about identity than answers: Why did my identical girls attach to identical objects while my fraternal triplet chose one so different? What kind of invisible imprints have my children left on their babies? What will I leave on mine?

When I was pregnant, people often asked how I would tell the identical girls apart. “Even the third might look the same,” they said with pinched brows, pointing to my giant belly, genuinely concerned for our postnatal days. Wondering the same, I bought nail polish in each of the girls’ assigned colors (pink, yellow, green) and planned to paint big toes. I bought color-coded onesies. We selected names, which we assigned to their anticipated birth order, and posted them above their cribs. I was afraid—as others must have been—that I might lay one baby in another’s crib, forever calling her the wrong name. (As though that would’ve mattered—would it have mattered?)

But when I stretched my shaking hand through holes in their NICU incubators to greet them for the first time—squinting through a haze of anesthetic nausea and exhaustion, struggling to stay awake, battling preeclampsia swelling and dizziness—I knew I would never need the polish. Olive-skinned, dark-haired and green-eyed, my fraternal triplet Gwen resembled my husband’s family. She was tiny and gaunt, weighing only 3 pounds, still curled in a ball like a fetus. Though resembling her twin, Patten weighed 4 pounds, had a birthmark on her forehead, and only wanted to be held against my warm chest. Ainsley weighed 5 pounds, had a birthmark on her thigh and ate voraciously, earning the name “Cheeseburger” from the nurses. Already, I could tell their differences from across the room.

As they gained weight and their birthmarks faded, the identical pair became interchangeable to grandparents, cousins and friends. Babysitters asked that I dress the pair in their colors, style their hair differently, announce frequently who was who. But to me, Patten and Ainsley were as different from each other as they were from their sister Gwen. Patten had developed a wry smile and a wary spirit, learning all the boundaries before she made a move. Ainsley had grown confident and independent, sitting sometimes by herself at the window to look out, as though dreaming of travel but knowing her home would always be there. If people didn’t always remind me, I would have forgotten two were “identical.” I would have referred to all three as “sisters.”

When all three started walking and talking (wee Gwen was the first—always the first—as though trying to distinguish herself from the two and needing an identity more unique than “the fraternal” or “different-looking”), the people closest to them could sometimes tell them apart. “I see the roundness in Ainsley’s face,” or “Patten has a scruffier voice,” they’d say. But, a day later, they went right back to calling Patten by Ainsley’s name or Ainsley by Patten’s name.

No one ever called Gwen the wrong name. Because of her recognizability, because of her difference, she evolved to become a mascot of sorts for the Todd Triplets. Besides her many physical differences, she is a tiny spitfire, bossing around kids and parents alike. One day, when I had all three 3-year-olds paint pictures, Patten and Ainsley chose red and orange and painted similar blobs on one end of the long paper. Gwen chose green, brown, and purple and scattered her paint in wild brush strokes all over. Even as I forget what they are, their preferences remind me that two shared a placenta and one hid in a ball under my ribs, a mystery, separate, waiting to unfurl wild brushstrokes on the great, blank canvas of life.

My husband and I do try to nurture our children’s separate identities. We moved so each girl, now 4 years old, has her own bedroom. We dress them differently, according to their personal tastes (with the exception of three identical blue “Sister Squad” shirts I couldn’t resist buying). We refer to Patten and Ainsley by their names instead of as “the identical pair.” I have now cut their hair in unique styles. We named all three without regard to rhyme or alliteration, the only commonality among them (we realized after we had already named them) being one “N” and one “E” in each of their names.

Still, to many besides themselves—and perhaps even to themselves—all three have no identity other than “the triplets.” “Here come the triplets,” my niece says as we walk through the door. “What are the triplets doing these days?” the women at my book club ask. Each of my girls will be known as one of “the triplets” when she goes to school, arriving at the same time and perhaps to the same classroom as her sisters, sitting next to one another during graduation and standardized tests. People will confuse who did what, telling stories that gloss over which triplet was the heroine of which adventure. Five years younger than my own sister, even I have been mistaken for her—still am mistaken for her—people overlapping our stories in implausible ways. We look alike, maybe even talk alike, but I am 4 inches taller, with a different hair color, a different profession and education, different friends and hobbies. Imagine how often the stories of my daughters—especially of the identical pair—will be confused for each other’s.

It is difficult, even for me, not to compare. Identical multiples share 100 percent identical genes at conception and less so (due to small, cellular changes) as time goes on. Fraternal multiples, however, share about 50 percent of their genes, the same as any siblings. With few exceptions, all multiples are raised in the same environment. If they’re like mine, they have almost never been separated. Watching triplets interact and grow is like observing one long, controlled study. If one reacts to a stimulus but her identical twin does not, for example, we immediately ask whether the cause is environmental. If the identical pair react the same but Gwen does not, we wonder if it is genetic. If all three react at the same time and in the same manner, I start to think their shared experience is to blame. Sometimes, I wonder if my identical girls’ differences are due to a split-second change in my tone, or a look given to one when she was a babe, or 10 extra minutes spent with one over the other. What if, I think, Ainsley had come home first from the NICU instead of Patten? Would Ainsley have become the more attached one? Or what if I could have given more skin-to-skin contact to Gwen in the NICU? Would she have grown calmer, more relaxed? I start to count the invisible imprints I have left on them.

I don’t know how my children will develop: if they will embrace their similarities or pursue their differences. Sometimes, when they fight and whine, “I want to be the only child,” I worry I haven’t separated them enough. Other times, when they hug and hold hands, saying, “I love you, sisters,” I dream of them all rooming together in college. I can’t imagine it is easy to be a triplet, even with the built-in friendships and three times the clothes and toys to share. I don’t know if it is good or bad that they (and I) know no different reality.

The uncertainties disappear as I watch them huddled together in our living room, the identical pair standing on either side of Gwen. Without talking or instructing, Patten and Ainsley bend their knees like platforms for Gwen to climb. Together, they build an impromptu pyramid. I cringe, waiting for one to fall, knowing I will have to comfort all three if they do. Instead, they laugh. Gwen stands on her sisters’ thighs, her eyes alight, finally the tallest of the three, and I realize, perhaps, I have less to do with their formation than they do, seemingly stronger together than apart.

I am OK with that, even if it means my children grow up confiding in one another before confiding in me. They have a closeness I have never experienced—a trust that the others will hold them up and make them feel bigger. But to me, my children will always be distinct beings. With me, at least, they are Patten with the wry smile, Ainsley with eyes of wonder, and Gwen, the tiny babe who arrived ready to conquer the world.