An I.V.F. Mixup, a Shocking Discovery and an Unbearable Choice

In the days after Daphna Cardinale delivered her second child, she experienced a rare sense of calm and wonder. The feeling was a relief after so much worrying: She and her husband, Alexander, had tried for three years to conceive before turning to in vitro fertilization, and Daphna, once pregnant, had frequent and painful early contractions. But now, miraculously, here was their baby, their perfect baby, May, with black hair plastered on her head. (May is a nickname that her parents requested to protect her privacy.)

Because everything about May felt like an unexpected gift, Daphna was not surprised to find that she was an easy newborn: a good eater, a strong sleeper. The couple settled May into her lavender bedroom in their home in a suburb of Los Angeles. Daphna, on leave from her work as a therapist, was grateful for the bounty of two children, overjoyed that she could deliver to her older daughter, Olivia, then 5, the sister she had begged for since she could speak in full sentences.

Alexander, a singer and songwriter, wanted to share his wife’s happiness, but instead he was preoccupied by a concern that he was reluctant to voice: May did not look to him like a member of their family. She certainly did not resemble him, a man of Italian descent with fair hair and light brown eyes, or Daphna, a redhead with Ashkenazi Jewish heritage. Alexander often turns to dark humor to mask a simmering anxiety, and in the days after the birth, he started to joke that their I.V.F. clinic had made a mistake. Later he would explain that the jokes were a kind of superstition, a way of warding off something threatening: If you say the horrible thing out loud, it won’t happen. But friends and family members were also commenting to him on the striking difference in appearance — Alexander’s mother, for example, told him, out of Daphna’s earshot, that she would have guessed that at least one of May’s parents was Asian.

Alexander would convince himself that everything was fine, only to be walloped once again by the suspicion that May was not his genetic child. Daphna, who was accustomed to calming Alexander’s worries, quickly tired of his nervous jokes about the clinic. Looking back, she realized that her consciousness was working on two levels, that her mind was laboring not to see what was fairly obvious. She often sought reassurance from a baby photo of herself that her mother sent her, in which she closely resembled May. But occasionally, when Daphna looked in the mirror, she would see her own face and think it looked strange — as if there were something wrong with her.

Trying to ease Alexander’s mind, Daphna ordered a DNA testing kit. But Alexander, threatened by its ominous presence on the night stand in their bedroom, was reluctant to go anywhere near it. Daphna grew concerned enough about Alexander’s low mood that she called his best friend for advice. That friend was the first person brave enough to tell Daphna directly what he really thought: At least one of them was not May’s genetic parent. His certainty startled Daphna. Suddenly, when she looked at May, she could see what he was seeing — she could understand Alexander’s alarm. Finally, in November 2019, they sent DNA samples off to a testing company. Then they waited.

Three weeks passed before the results appeared in Alexander’s inbox. By then, May was about 2 months old, the point in babies’ lives when they can track their mothers’ movements around a room, when they are comforted by being picked up, when their faces brighten at a caregiver’s approach. May had just started smiling back when her family members smiled at her, an emotional call and response that delighted Olivia, who often watched TV with May comfortably nestled by her side.

Alexander opened the email on his phone, as Daphna, holding May, paced around their bedroom. She saw her husband’s face immediately look drawn; his body language registered defeat. He read out loud: “99.9 percent likelihood, not a match for the father.”

“But what about me?” Daphna asked twice, quickly. She was sure that one of them must be May’s parent, the way some people who play the lottery feel certain, no matter how irrationally, that this time they’ve picked the right numbers. Alexander scanned: “99.9 percent likelihood,” he told her, “not a match for the mother.”

Ten minutes later, a babysitter arrived to watch May while Alexander and Daphna took Olivia to see “Frozen 2,” a long-promised outing. In the theater, they sat on either side of her, tears running down their cheeks in the dark, trying to understand what this news meant for their family. If the clinic had given them another couple’s embryo, what did that suggest about the fate of their own embryos? If they tried to find out and informed the clinic of the error, could they end up losing May? Even if they did nothing, could they lose May to her genetic parents, who might already be desperately trying to find her?

In the days that followed, Daphna learned with mounting distress that the law generally privileged genetic parents in the very rare cases like theirs. Just a few months earlier, a lawsuit had made the news involving a woman in New York who gave birth to two boys, neither of whom, it became obvious after their birth, shared her and her husband’s Korean American ancestry. Nor were the boys related to each other, the clinic determined when it investigated. The embryos came from two other couples, both of whom sued for custody. The Korean American woman fought to raise the boys but lost in court. She was forced, heartbroken, to relinquish her babies to their respective genetic parents.

Daphna and Alexander were under no legal obligation to tell anyone about the DNA test results, but they knew, with an agonizing clarity, that they had to contact the clinic to share what they had learned. They felt that they owed it to May to try to find her genetic parents — even if it meant losing her. “We didn’t want to be those people who were so desperate for a baby that we were going to deprive someone of theirs,” Daphna told me. “It felt like a kidnapping.” They also wanted to know what happened to their own embryos: Were they all still in the lab? If any were missing, had they been accidentally destroyed — or transferred to someone else? The couple retained a surrogacy lawyer, Andrew Vorzimer, who reached out to the clinic, the California Center for Reproductive Health, which opened an investigation.

Life took on a nightmarish quality for Daphna, who felt the possible loss of May every time she held her close. Some days she felt numb; some days she cried alone in her bedroom. Every time there was a knock on the door, she was afraid that it would be a lawyer or social worker with official-looking papers, there to take May away. Rather than distancing her from May, the thought of losing her only deepened the tenderness Daphna felt toward her. “I felt like I had to pour as much love into her as I could,” she told me, “almost like the way you store up for winter.” Olivia, who knew nothing of her parents’ concerns, also grew more attached to her baby sister. Daphna once went to lay May down in her crib and found, where the pillow would be, a drawing of a rainbow that Olivia had put there as a gift for her little sister.

On Dec. 6, Vorzimer called as Daphna was changing May’s diaper. He had news: The fertility clinic had identified May’s parents. The clinic saw couples from around the world, but May’s genetic parents, astonishingly, lived only 10 minutes away in a nearby suburb. Alexander’s mother would turn out to be right: The father was Asian American; the mother was Latina. “So I just lost my baby,” Daphna said to Vorzimer, holding May in her arms. “I just lost my baby, right?” He couldn’t be sure what it meant, he told her. But in the coming days, he relayed more news: The other family had a baby the same age as May, a little girl with blue eyes. She was Daphna and Alexander’s genetic child, and her name was Zoë.

The other couple did not have the prolonged process of waiting and discovery that Daphna and Alexander had. Instead, there was an urgent phone call from the clinic, their fertility doctor weeping as he explained that there had been a terrible mistake: They had been raising the genetic child of another couple, who had been raising theirs. The conversation was a shock that plunged them into grief, even if Zoë’s mother, Annie, wasn’t entirely surprised. On some level, she had been waiting for a phone call like that one. (Annie is a nickname, and her husband’s name is being withheld at their request to protect their privacy.)

Annie and her husband had their first child, a son, when she was in her early 40s. He was about 2 when they turned to I.V.F. to try to have a second. When Annie gave birth to a daughter with surprisingly fair hair, the extended family on both sides took it in stride as one of life’s flourishes of fate, a reminder of the mysteries of biology.

In the first weeks after the birth, Annie felt that all was as it should be: Zoë latched easily, and Annie loved the closeness she felt when she nursed her, their bodies aligned in mutual comfort in the hazy hours of the early morning. When Zoë was about 2 months old, her eye color developed into a deep blue, which Annie found confusing enough that she asked her pediatrician about it; he reassured her that recessive genes surprise parents all the time. But Annie still felt uneasy when friends commented on her baby’s looks — how light-haired she was, how remarkable it was that Annie could have given birth to her. After the phone call from the doctor, Annie, who was already experiencing bouts of melancholy after Zoë’s birth, sank into a depression. She had never felt closer to her daughter, but because of the shock, she thought, her milk dried out. She could no longer nurse.

The day after Christmas, the two couples exchanged voice mail messages and agreed to meet the next day at a law firm near their homes. Alexander was a compulsive documenter who often captured video of important family moments, and he planned to use his phone to create a record of the event. He and Daphna arrived first and waited in a conference room to meet the people who might determine May’s fate. They stood awkwardly by a table as the other couple entered. Annie was several inches shorter than Daphna, with the dramatic looks of a movie star, her hair long and dark. Her husband was trim and about Alexander’s height. They knew his face well — because it was their daughter’s face.

Daphna walked up to Annie, and the two women stared at each other. Then Daphna leaned down and hugged Annie, who hugged her back, their embrace close and quiet. They stayed that way, clinging to each other, while Alexander and Annie’s husband shook hands, exchanged names, stuck their hands in their jacket pockets and looked everywhere in the room but at each other. When the two women pulled apart, Daphna said to Annie, “How are you doing?” Annie, her face grave, answered: “Terrible.”

The two couples relaxed: Each sensed in the other a basic decency; they took comfort in being with other people who could fully understand their surreal dilemma. They talked for a long time about how painful any resolution of the situation would be. They cried together. At times, they sat in silence. Alexander could sense that both mothers were avoiding having to speak plainly of what the future would hold. Finally, Daphna asked the question that was hovering in the air: “So, what are we going to do?”

May and Zoë were no longer newborns but babies who had, by then, spent three months hearing their siblings laugh, smelling their mothers’ scents, seeing the particular shade of dark that descended in their rooms when night fell. Could the parents now possibly rip them from all the comfort they’d known, in the name of some genetic allegiance? The known cases of I.V.F. mix-ups like theirs were rare enough that the two couples had little precedent to turn to for guidance.

Daphna knew from her training as a therapist that, at 3 months, the girls weren’t yet fully awake to the world. Their senses were still developing; their vision was cloudy beyond close range. She and Alexander felt bonded to May, and they felt that she was bonded to them — she knew her name and lit up when they looked into her eyes. But they knew that children who are adopted into loving homes, even at much older ages, are expected to thrive, especially if their early caregivers were nurturing. “It’s a difficult change — but doable,” Beatrice Beebe, a psychology professor at Columbia University’s medical school who studies infant development, told me. “The baby would have to learn a whole new set of patterns, but babies are fantastic learners.”

After going over every nuance, every emotional response and logical argument on every side, Alexander had resolved that they should switch the babies. He felt, more so than Daphna, the imperative to raise the child they’d intended to bring into the world. “There’s a pull, genetically,” he said. That Zoë would live so close, that he would know of her existence but not raise her felt like “upside-down world,” as he put it. But heading into the meeting, he had no way of knowing what Annie and her husband felt — whether they would fight to maintain custody of Zoë.

When Daphna posed the question to the room, Annie looked bewildered. “I don’t know what to do,” she said. Both of them wept as the conversation circled closer to a resolution. Finally, Annie’s husband said out loud what Annie knew, going into the meeting, would most likely be the collective decision: They would switch the babies. Alexander felt relieved that someone had said it so clearly; he knew that neither of the mothers ever would. As shaken as they were, the couples were in agreement.

But how to do it? They knew they couldn’t just turn their babies over — it didn’t feel healthy for Zoë and May, and at any rate, the parents weren’t emotionally ready. Should they make the transition with regular visits over six months? Three months? They decided they would start feeling their way toward this major shift. The babies, they all believed, would adjust. Privately, each couple wondered if they could, too.

Having made it through one dreaded conversation, Daphna and Alexander now prepared for another: They had to tell Olivia. How to explain to one young daughter that you are voluntarily giving up another? They resolved to make it as simple as possible; their voices would be bright and reassuring, their emphasis on the new baby who was going to come into their lives — one who looked just like her. The day after Daphna and Alexander met with Annie and her husband, they approached Olivia, who was lying on the couch in the living room, a blue blanket half-draped on her.

“What if I told you you had another sister?” Daphna started out. Olivia looked mildly curious and stared at her mother’s stomach, clearly imagining she was pregnant.

Daphna asked if she had ever noticed that May looked different from the rest of the family. “Yeah,” Olivia responded, which somehow surprised Daphna, because she had never mentioned it. The “So what?” in Olivia’s tone was heavily implied. Daphna explained to Olivia that there was another baby who was a part of their family and that she was gaining a sister after a bit of a mix-up. Daphna said nothing about making a switch, but Olivia was quick to figure it out.

“Wait,” she said, sitting up abruptly. She asked: Did this mean they were losing May?

Alexander responded, reflexively: No, he assured her, we’ll always have her. Daphna groaned internally. That wasn’t true, and it would be an awful promise to break; at the same time, she knew that, in the moment, it seemed like the only possible answer.

Alexander told Olivia not to be scared, but Olivia started shutting down. She made a small whimpering noise. She asked again: Were they going to give her sister away?

As Daphna tried to comfort Olivia, she burned with anger at the clinic. Somewhere along the way, a mistake had been made. Daphna knew errors could happen when embryos were being tested for genetic birth defects or when they were being transferred to the mothers. Someone must have been careless, she thought, someone who had, unknowingly, thrown her family into chaos. Alexander felt that he had been played the fool — made to love a baby who wasn’t his to raise.

Eventually, the couple hired another lawyer, Adam Wolf, and filed suit against the clinic, alleging medical malpractice, negligence and breach of contract. Wolf, who specializes in suing fertility clinics that have been responsible for life-altering errors, says he had encountered fewer than 10 cases in which an embryo was transferred to the wrong woman. But he estimates that over the past decade, he has represented more than 1,000 plaintiffs accusing clinics and their suppliers of misconduct or negligence, most commonly because embryos in their care have been accidentally lost, damaged or destroyed.

In one instance, he represented a couple who asked a fertility clinic to test their embryos for a genetic mutation the husband carried that is associated with a type of often-lethal stomach cancer. The clinic helped the couple conceive a child, whom they were told was free of the genetic mutation. But a year later, when the parents returned to the clinic to have a second child, they discovered that the clinic had made a mistake: Their 1-year-old was a carrier.

Wolf believes that the public becomes aware of only a fraction of the errors that occur in fertility-clinic labs. In Zoë and May’s cases, as in the case of the twins carried by the Korean American woman in New York, the mistake was apparent because the children were a different race from the birth parents. In most instances, parents who accept and bond with their baby may never suspect something is wrong. Even when discovered, such mistakes rarely make the news. “Most of my cases you never hear about, because we settle them before we file lawsuits,” Wolf said. “And the settlement agreements have confidentiality agreements, because the clinics want to ensure that there will be no negative publicity as a result of its error.”

I.V.F. procedures are underregulated relative to most medical procedures, says Dov Fox, a law professor at the University of San Diego with a focus on bioethics. States do not mandate that fertility clinics report preventable and damaging mistakes when they happen, as is required of hospitals. Some emblematic problems, Fox told me, included clinics or labs relying on pen-and-paper labeling systems and faulty screening measures; Wolf cited a failure of clinic employees to respond to alarms on the freezers that store embryos. “I sometimes think of our lawsuits as the policing of the fertility industry,” Wolf said, “because nobody else is holding them accountable.”

Now heavily dominated by private equity, the industry is rife with for-profit, high-volume fertility clinics operating in a regulatory dead zone. Oversight of fertility clinics has been limited, Fox said, because of the challenges it poses politically: Although many conservatives would like to impose restrictions, including limiting the number of embryos a lab can create, they have historically not wanted to jeopardize efforts to restrict abortion by also attacking I.V.F., which is broadly popular. Many Democrats, meanwhile, have been reluctant to regulate the industry for fear of opening the door to restrictions that might, for example, limit who is eligible for I.V.F. (as in some countries, where gay couples are excluded). Fox expects that the overturning of Roe v. Wade will lead to new scrutiny of I.V.F., which might ultimately threaten its wide availability.

On the last day of the year, Daphna and Alexander stood in their living room, waiting to meet Zoë for the first time. They could hear her crying as Annie and her husband approached their front door. The sound was eerily like Olivia’s cry at that age, as if emerging from a time capsule. Listening to it crystallized everything Daphna and Alexander had been feeling for the past two weeks — that there was a child out there in the world, so close, but whom they couldn’t see or hold or comfort. Daphna bounced May in her arms as they waited for the doorbell to ring. Alexander swore a nervous curse, and May stared at him, a look of consternation on her face, reaching for her father with her tiny hand. Both couples had made other plans that day for their older children; the parents knew it would be hard enough to manage their own emotions without having to manage the siblings’ too.

The bell finally rang, and then Annie was inside, smiling at the baby in Daphna’s arms, reaching for her. “I’m sorry,” she said, weeping, her breath ragged. She kissed May’s cheek twice and buried her face in the crook of the baby’s neck. She sat down on the couch, her backpack still on. “How are you? How are you?” she asked, holding May in her lap so she could marvel at her face through tears.

“Hey, Zoë, this is your Mama Daphna,” Annie’s husband said as he unbuckled the baby from her car seat. “You want to go to your mommy?” Daphna, gasping, smiling, picked Zoë up. She was shocked by how different Zoë felt, how big compared to May — she realized that none of the clothing she’d bought for this daughter would fit.

Soon the husbands were holding the babies. Both mothers’ gazes veered from the sight of their own child in someone else’s arms to the sight of the other child in their husband’s arms. Each was doing the best she could to let the other mother have all the psychic space she needed with her daughter.

For almost two weeks, the families visited each other every day, sometimes at Daphna and Alexander’s house and sometimes at Annie and her husband’s house. Often the two mothers did what Alexander came to think of as “the mama dance”: Each would go to change a child’s diaper, then step back for a moment. “Is it OK if I? … Would you rather that you? … ” They had endless tiny details to discuss: Does she use a binkie? How long does she nap? Do you hold her until she falls asleep and then put her down, or just put her down? What’s her favorite bedtime music? How much did she weigh?

The couples were inventing a new kind of relationship as they went, and it was far from a given that the transition would go smoothly. For others in similar circumstances, the attempt at maintaining connection had ended in recrimination, as in the case of Donna Fasano, who in 1998, because of a clinic’s mistake, carried another couple’s embryo to term along with her own. (The mistake was evident because Fasano and her husband are white, and one of the two babies she delivered was Black.)

When the babies were 5 months old, the parties signed an agreement granting the genetic parents, Deborah Perry-Rogers and Robert Rogers, custody of their child and allowing Fasano and her husband to visit him twice a month. The visits quickly became tense. Perry-Rogers and her husband renamed their son, but when Fasano visited, lawyers for the couple claimed, she continued to call him by the name she’d given him and referred to herself as “Mommy,” which his new parents could not abide. Eventually, after more litigation, a judge denied the Fasano couple their visitation rights.

May’s and Zoë’s families were the victims of a fluke mishap, but they also seemed to be the beneficiaries of a fortuitous alignment: Financially, they were on similar footing, which meant that neither couple feared depriving their child of that advantage. Neither couple was particularly religious in practice. Even their parenting styles were similar: nurturing, attentive and gentle. There were some evident differences — Annie was home with the children, while Daphna worked full time — but for the most part, their similarities were as unlikely as the circumstances that brought them together.

In January, the couples decided that they were ready to take the next step — a daytime visit for each child alone with her genetic parents. Daphna sent May off to spend a few hours with Annie and her husband and was knocked over by a wave of grief as soon as she was by herself with Zoë, the child she had waited so long to have. Alexander found Daphna crying, sitting on the floor, as Zoë rested calmly in an automatic swing, the one May had swung in so many times. Daphna felt trapped: For every happy emotion, there was an equal and opposite adverse emotion. “As much as I’m so happy that Zoë is here and that we’re finally home with her, I just miss my May so much,” she told him through tears. “I know they’re taking care of her, but they don’t know her either.” She looked over at the swing. “But Zoë’s here. I know it’s wonderful.”

On Jan. 16, the families each had their babies overnight for the first time, and Daphna started to feel the connection she had been longing to feel. When she gave Zoë a bath before bedtime, she took her daughter in her arms, inhaled the scent of her head, felt her soft downy hair — somehow now she smelled like home. Like their towels, their shampoo, maybe even their pheromones. Daphna couldn’t help thinking of May, 10 minutes away at Annie and her husband’s home. May seemed farther along developmentally than Zoë, and Daphna worried that the change would be harder for her. That night, in fact, May was crying inconsolably. Annie was distraught that she could not comfort her, her heart breaking for a baby she already loved but who was sobbing, she was sure, for a mother Annie could not possibly be at that moment.

The couples had discussed when they were going to switch the girls permanently, but when the time came, somehow Daphna had not fully understood that it was imminent. The morning after that first sleepover, when Annie and her husband indicated that the girls should stay where they were, Daphna was stunned — what felt like the swiftness of the decision saddened her. Even so, she agreed that it was time; the girls were already 4 months old, and the back and forth was proving hard on everyone, especially the older siblings.

On Feb. 11, the two families met at a courthouse. They had been giving each other space, and that day was the first time they had seen each other since the switch. They formalized their new parenting arrangement, signing papers that reclassified the carrying mothers as surrogates. It was real; it was in writing. Daphna shared the news on Facebook with friends and family, many of whose messages she and Alexander had been ignoring. They hadn’t known what to say. Trying to explain was exhausting.

In the days and weeks that followed, Alexander came to dread the hours after bedtime, when Daphna, who kept her emotions in check all day for Olivia and Zoë, broke down, sobbing for much of the night like someone in physical pain. At other times, Daphna would feel May’s presence and turn to Alexander. “She needs me,” she would say. “I can feel it. I’m going over there right now.” Alexander could summon the calm needed to talk her down, but he started suffering from panic attacks for the first time in his life.

Daphna and Annie had agreed that no matter what, they would do whatever they could to help the older siblings cope. On Feb. 13, Daphna texted Annie because Olivia was weeping, crying that she missed May. Daphna didn’t want to put Annie in a difficult position, so she wrote, with considerable understatement, that Olivia was “having a really hard time.” Twenty minutes later, Annie and May were at her door. Alexander took photos of May, chunky and laughing, in the arms of Olivia, who was flashing a smile that hadn’t been seen since her sister left the house. Annie acknowledged, tearily, that May also looked happier than she had since the switch. They put the two babies next to each other and photographed them gazing at each other from their respective blankets: May with a thumb in her mouth and a hand on Zoë’s face, Zoë’s hand reaching out to touch May.

In a text later that day, Annie promised Daphna that she would give May all the love she could, and that she had faith that Daphna would do the same for Zoë. “You’re a great Mommy,” Annie wrote. “We can definitely visit each and check how our girls are doing. It’s so hard. I don’t know how to let go.”

Daphna wrote back: “What if we don’t ‘let go’? What if we just have 2 babies? We share them. We have to find a way to have both babies. Spend a lot of time together. Raise these girls together.”

Annie responded quickly. “Yes, let’s raise them together,” she wrote. “Let’s have two babies.”

The two families started meeting more frequently, becoming closer but sharing only so much of what was going on at home. Privately, Annie was flooded with anxiety. Sometimes, when May cried, Annie didn’t feel the same physical tug she felt for Zoë, a void that she filled with guilt and self-recrimination. They say the blood calls, she thought, gazing at her baby — why wasn’t it calling now? She loved May profoundly, but that love was somehow different from what she felt for Zoë, who had imprinted on her heart. Annie tried to stay buoyant for her son, but her efforts could be sabotaged by his innocent sweetness. “Where’s Zoë? I want Zoë!” he would say, looking bewildered. Annie would try to reassure him — now May is here, she would tell him, trying to sound cheerful, and Zoë is with her Mama Daphna and Daddy Xander.

Like Daphna, Annie was eager to make her daughter’s transition as seamless as possible. Daphna used to bounce with May on a big yoga ball, which she gave to Annie, so now Annie bounced with May on a big yoga ball. Daphna told her that May liked being swaddled, so now Annie swaddled her. Daphna said May slept better in her own crib, in her own room, with the sound machine on and the shade drawn; Annie, who was used to having Zoë sleep in her bedroom, would instead go to May’s bedroom at bedtime and hold her tiny hand through the slats of the crib until she fell asleep. Sometimes, when Annie bounced with May on the ball, she had the strange sensation that it wasn’t just that the baby had been switched but that she herself had been transformed — that in trying to replace a different mother, she had become a different person. She was depressed enough that her own mother, who had planned to stay with her for just a few months after the delivery, decided to extend her visit.

The couples had known each other for only three months when the pandemic hit in March 2020, but by June, they decided to form a pod. Annie’s son and Olivia grew as close to each other as they were to their younger siblings. They played with Legos, made slime, stole food off each other’s plates and longed to see each other if too many days went by without a visit. Annie was always eager to see Zoë, but when the two families gathered, her emotions could be unpredictable. During one visit to the Cardinales’ home, when Zoë, who had a rash, cried loudly, Annie almost shook from the effort of not rushing to take Zoë in her arms.

Daphna, too, felt that she had been transformed. From the moment she learned the fertility clinic had located May’s parents, she knew she would be changed by what was to come; she just didn’t know who she was going to be on the other side of it — would she still like that person? Many times, during that first year, she wasn’t sure. Usually so even-keeled, she was now more easily overwhelmed, quicker to snap. She gave Zoë all the love she had to give: She gazed into her eyes, held her and walked with her, sang softly into her ear, tickled her tummy gently to make her laugh. But sometimes, even when she was feeding Zoë in those murky, dreamy hours of the early morning, she would have a haunted sensation. I have the wrong baby, she would think with a start of panic.

That spring, the minister who married Daphna and Alexander reached out after learning about what happened from the update that Daphna posted on Facebook. The minister had an idea: What if she merged the two families in a formal ceremony? Because a Covid lockdown order was still in place, the “family joining ceremony” would be virtual for everyone except the eight of them, who gathered in Daphna and Alexander’s living room around the time of the girls’ first birthdays, in September. The couples expressed their commitment, and the minister said a blessing. Then each family member who was able picked a color of sand and poured it into two different molds decorated with the silhouette of a tree, representing their growing family. The colorful family trees sat on mantels over the fireplaces in each of their homes.

The merging of their families was an act of hope, like a wedding, which didn’t mean their problems were behind them. Daphna worried that although she could still give love, she was not as receptive to receiving it. She felt distant from Alexander, whose panic attacks were growing worse, especially after visits with May. Sometimes they were so bad that he was sure he was having a heart attack; once, they called an ambulance. Instead of making Daphna more caring toward her husband, she felt herself withdrawing out of self-protection. What if something happened to him, too?

Something shifted for Daphna when the babies were about 15 months old. Zoë, by then, was already standing on her own and walking. One morning, Daphna left her momentarily to take out the trash. She was gone less than a minute, but when she came back, Zoë was wailing, staring at the door, crying with an operatic scale of sorrow that only a child that age can fully embody. It hit Daphna in that moment: To Zoë, she was just her mother. There was no before. There was just the wholly consuming dependency and desire that a 1-year-old feels for the woman whose face has beamed into her own with love and concern more than any other. Daphna hadn’t even realized that she still had a wall up — but now she realized she had to take it down. She had to try, as she thought of it, “to open another chamber of my heart.”

Both families, the previous December, had suffered through the girls’ first Christmas, afraid of losing their babies. Neither imagined that the next year they would be celebrating with that baby and another baby — with a whole new family — crammed together around a table. That Christmas, and every one since, the bases of their trees were buried in mounds of toys for the four children. Annie and her husband came loaded down with bags and bags overflowing with wrapped boxes, adding to the bounty that Daphna and Alexander had already amassed. Both sets of parents sensed that the excess did not so much reflect their joy as it did their lingering fear that their babies had suffered — that they had not been able to protect them. “It’s the guilt,” Daphna said. “We both feel so guilty.”

May and Zoë are now 5. They’ve celebrated holidays and birthdays together, swung on countless swings in synchrony, shared bubble baths and sliced apples and giggled under the covers when hiding, as a team of two, from Alexander in a game of hide-and-seek. They consider each other sisters. For the last two years, the girls went to the same preschool. Every day after school, they would beg Annie and Alexander, who did drop-off and pickup, for more time to play together. Annie took great pleasure in seeing Zoë so regularly; Alexander felt the same way about May. May still calls him “Daddy Xander” and Daphna “Mama Daphna,” and Zoë addresses Annie and her husband the equivalent way.

As close as they are, the girls have developed distinct personalities, and Daphna often thought about how each of them might be different, had she been raised entirely in her original home. Zoë, who had been slow to move and late to talk (it turned out she was born with a tongue tie), now was the louder of the two, more excitable. Daphna wondered whether she had changed as she got used to their family’s more boisterous energy. (“We’re like — the Louds,” Daphna said.) Zoë is devoted to the family dog, Cece, a rambunctious mutt and a licker. May, by contrast, climbs into her mother’s arms for comfort if the dog comes too close.

With time, Daphna and Alexander felt their sense of steadiness in their family returning. They had been outspoken about their ordeal to the media and pursued their malpractice lawsuit in the hopes of holding the clinic accountable, but in 2022 they decided to settle, in part because they did not want to risk having to put Olivia on the stand. (The details of the settlement have not been made public. A lawyer for the clinic declined to comment on the facts of the case but said that “the parties settled amicably.”) With the fight finally over, Daphna and Alexander realized they could put down the boulder of anger and resentment they had been carrying together. They could breathe. They could be grateful for the time they spent with May — May, whose favorite color was rainbow, who still could fall asleep, from the exhaustion of an outburst, in Daphna’s arms — and fall in love with Zoë, who harmonized as soon as she could sing, who snuggled up to Daphna for naps, who had a mind for numbers, like Alexander’s grandfather.

Every so often, Alexander would look at his phone, and there would be a text from Annie about a listing for a home on the market in her neighborhood. Once, when the girls were about 3, Annie sent them a listing for the house that was right next door. She was hopeful that they would buy it. They could take down the fence, have one big backyard — it would be as close to their dream for a shared house as they could get. Daphna and Alexander went and looked, wandering their way through the high-ceilinged house. They loved the idea of living next door, but the house was too expensive; there were limits to how much they could do to accommodate their mutual longing.

This year, for the first time, May and Zoë will be going to different schools. The kindergarten in Daphna and Alexander’s neighborhood would have been an even longer drive for Annie than the one to the girls’ preschool, and the commute would have made it harder to get her son to his after-school activities. To ensure that they would all see one another at least once a week, Annie proposed that the girls sign up for ballet on Sundays, a plan the Cardinales embraced. They were just as committed to maintaining the bond. Sometimes Alexander talked to Daphna about how much easier their lives would be if they moved to Northern California, where they had more family, but the thought always ran aground: What about May? They were still too close to her to seriously contemplate moving away.

May’s kindergarten started before Zoë’s, and both sets of parents were excited and nervous for her on her first day of school. “The teacher said she did great,” Annie wrote to their group text thread at the end of the school day. “Yay! Success!” Daphna responded. Annie wrote that May had drawn something at school for Daphna, but she had been instructed not to send a photo of it — May wanted to give it to Daphna in person.

That afternoon, Annie took her to the Cardinales’ house, where May presented Daphna with the picture. It showed a woman with red hair like Daphna’s, her pregnant belly bulging out to hold the baby May had drawn inside. The mother is holding the hand of a little girl, the baby’s older sister. At first, May told Annie that the picture was of Annie, but then she said what Annie already knew: It was a picture of Daphna. Annie and Daphna marveled over the crayon drawing — over how complicated it was that on May’s first day of school, her first day of separation from Annie, the person she was thinking about was Daphna. Annie wasn’t threatened; she knew how devoted she and May were to each other. If anything, Annie seemed almost awed by the complexities of a loving 5-year-old’s mind. “They’re still working it out,” she said, amazed.

In moments like that, Daphna reflected on how complicated her feelings about May still were. There was guilt that she gave May up, but also another sort of guilt — the knowledge that although she still loved May, she had had to change the shape of that love into something new, for everyone’s sake. “I don’t know how to let her back into my heart the same way,” Daphna told me. She and the other parents all tried to normalize what happened, cheerfully answering questions about who started out in whose belly and why, but they knew that as the children got older, they would have more troubling questions — questions about chance and choice and sacrifice and compromise. The parents might not have the answers to those questions; they would simply say that they did the best they could.

Don’t call it a happy ending, the children’s parents would say; it’s not. It’s the happiest ending possible, which is, still, more than they could have hoped for.