This article is part of The State of Science, a series featuring science stories from public radio stations across the United States. This story, by Nina Feldman, was originally published on WHYY.

Heather and Norm have had their share of disagreements. Their separation seven years ago and the ensuing custody battle were contentious. But over the years, the pair has found a way to weather disputes cordially. They’ve made big decisions together and checked in regularly about their two kids, now ages 9 and 11.

But the rhythm of give and take they so carefully cultivated came to an abrupt end last fall, when it came time to decide whether to vaccinate their kids against COVID-19 — Heather was for it; Norm was against. (WHYY News has withheld their last names to protect the privacy of their children.)

In Pennsylvania, decisions about children’s health must be made jointly by parents with shared legal custody, so the dispute went to court. And Heather and Norm weren’t the only ones who couldn’t come to an agreement on their own. In the months since the vaccine was approved for children, family court judges across the commonwealth have seen skyrocketing numbers of similar cases: Divorced parents who can’t agree on what to do.

When you can’t decide among yourselves

Heather and Norm had a nasty divorce, they both say so. Drawn-out court battles and arguments that bled onto social media lasted years after their initial separation. But once the dust settled, somewhat miraculously they found they agreed on a lot.

“If someone would have told me in the middle of the divorce that, you know, sometime in the future, you and your ex-wife are going to be able to just call each other on the phone and just have a chat, I would have said no way,” said Norm. “That is totally impossible.”

The two parents even created similar environments for their kids to grow up in, at least superficially.

On a bucolic 3-acre lot in Montgomery County, Heather runs a small farm where she grows rare botanicals that she supplies to local restaurants, plus a veggie garden for her family. She keeps bees and a meticulously designed, rustic chic home.

Her ex-husband lives about 20 minutes away, just across the Chester County line, where he spends much of his time in a barn out behind his house growing rare mushrooms, which he also sells to local restaurants. The area where Norm does paperwork in the barn smells vaguely of nag champa, and a slender copy of the Tao Te Ching is nestled between invoices on his desk.

Both park big pickup trucks in their driveways. Both have massive trampolines for their kids to jump on.

When the pandemic started, both parents adjusted nimbly to accommodate virtual school for the kids. Soon, though, they agreed that arrangement was taking a toll on both children, especially their son, who is older. Usually a good student, he was getting frustrated by electronic assignments, turning in homework late or not at all. He started developing an irrational fear that a tornado was going to hit, said Heather. Both parents agreed it would benefit their children’s mental health to be back among classmates as soon as that was an option.

Heather was nervous about the kids being in school before they were eligible to be vaccinated, but she assured herself that the time was coming soon, and that when it did, it would be a no-brainer

“It gave a sense of control about all of the things that have been uncontrollable for the past two years,” she said of the vaccines.

But Norm had a different calculus.

The fact that serious cases of COVID-19 were less common among kids made him feel as if his children being unvaccinated was relatively risk-free. On the flip side, Norm reasoned, the vaccines are very new, meaning there isn’t data on possible side effects years or decades out. And while he acknowledged that the number of cases of initial serious side effects was hard to pinpoint, he didn’t want to take any chances.

“If there’s any risk whatsoever [of the vaccine], that greatly outweighs the risk of not getting them vaccinated,” he said.

It’s important to note that COVID-19 is not risk-free for children. During the omicron wave, young children who were not yet eligible for vaccination were five times more likely to be hospitalized with COVID than when the delta variant was more prominent. The majority of those children had no underlying conditions.

Still, children hospitalized with COVID represent a small proportion of hospitalizations, and just over 1,000 children under 18 have died of COVID since the pandemic began.

To demonstrate that his position was, in fact, a result of calculated risk and not political ideology, Norm pointed out that he made the choice to get vaccinated himself. As a 45-year-old, he figured, the potential benefits of being vaccinated outweighed the risks.

“It makes sense for me,” he said. “But again, in my mind it does not make sense for a 9- and 11-year-old healthy child.”

Their disagreement about whether to vaccinate their kids was not Heather and Norm’s first pandemic dispute, but it was the most alarming to Heather. Earlier, she had heard from her kids that their dad encouraged them not to wear masks. (Norm said he believes that most cloth and surgical masks aren’t effective at preventing transmission of SARS-CoV-2, so unless kids are going to wear heavy-duty N95s, masks are not worth it.)  Heather was concerned by this, but also knew co-parenting is an exercise in choosing battles. She was unsettled, but ultimately figured it was behavior she couldn’t influence.

“My bubble isn’t just my four-person household,” she said, referring to her kids and her partner. “It extends to another household that I don’t have much input into or control over.”

The vaccination issue was different though. It felt more fundamental to the kids’ safety and well-being. Heather tried to reason and plead with Norm. She tried analogies. It was like letting them ride in a car without a seatbelt, she argued.

“Let’s wait and let them play in traffic and see if they get hit by a car, not everyone dies from that,” she offered, provocatively.

The two had been unable to come to an agreement by the beginning of November, when the Food and Drug Administration authorized the Pfizer vaccine for 5- to 11-year-olds.

Heather said she thought dozens of times about just going ahead and getting her kids vaccinated. The omicron wave and the holidays were on the horizon. Once it was done, there would be no undoing it.

But it wasn’t quite so simple.

Like most divorced parents, Heather and Norm share legal custody of their children. That means they must make decisions together in three main areas: school, health, and religion. If parents can’t come to an agreement on their own, often a mediator is brought in. If a mediator can’t resolve the issue, it could go to a hearing.

If one parent were to act alone by vaccinating their kids, or enrolling them in a new school against the other parent’s wishes, it would be considered a violation of the custody agreement. That parent would technically be in contempt of court.

There is a range of consequences for such a violation, but it’s akin to points on a driver’s license, or a mark on your permanent record. Too many strikes could lead a judge to make a broad decision about whether that parent deserved custody of the children at all. Not wanting to risk a demerit, Heather decided to take the matter through formal legal channels, in family court.

A mediator would not resolve the matter, and passed it along to a judge. Heather anxiously awaited a hearing date.

In the meantime, the kids’ unvaccinated status severely hampered their lives, she said. They were sent home from school to quarantine a number of times because of COVID exposures, while their vaccinated classmates were allowed to remain in class if they tested negative. The family was uninvited to a trip with friends because that family preferred everyone to be vaccinated.

The holidays came and went. A hearing date was scheduled for February.

Vaccine custody cases are on the rise

Heather and Norm are among hundreds of divorced Pennsylvania parents bringing similar cases to court. Hillary Moonay, a family law attorney at Obermeyer Law in Bucks County who  represents families in custody cases, said her firm has seen a surge in custody cases dealing with all sorts of COVID disputes.

Early in the pandemic, it was about whether parents were taking appropriate masking precautions or with whom a child should stay if a parent was exposed, she said. But once the vaccines were approved for minors, things really took off.

“I’ve been doing this for 25 years, and in that time frame, I’ve probably seen two to three cases related to disputes over children getting vaccines,” said Moonay.

Now, she estimates that her family law firm, which has roughly 20 attorneys and offices in Pennsylvania, New Jersey, New York, and Delaware, sees at least one case like this per week.

The scope of judges’ decisions in these cases can vary widely, said Moonay. A narrow ruling would grant one parent decision-making power solely on the issue of COVID vaccines. But if a judge felt one parent’s position skewed so far outside the best interest of the child, the judge could determine that parent should not have any decision-making power going forward. Moonay said she has seen both outcomes, but that one thing is certain: These disputes feel more high-stakes and more intense than other cases.

“Parents have much stronger feelings about it than they do over a lot of other custody issues,” she said.

In her experience, Moonay said, judges tend to lean heavily on the medical advice of pediatricians and look at the children’s vaccination history in making their decisions. If none of that contradicts the notion that the child should take the vaccine, the judge is likely to recommend it. And, she said, judges are on the lookout for signs that one parent’s position may be politically motivated.

“In some cases, we have the evidence to show that because parents have posted things on social media or have spoken out at school board meetings to show that maybe their position is more than what it looks like in court,” she said.

In Heather’s case, the children’s pediatrician did not provide a letter recommending that the kids get vaccinated. The Kimberton Clinic, which describes itself as practicing holistic medicine, offered a note that neither child had any health reasons not to receive the COVID vaccine, but that it would not recommend it outright. Instead, the clinic simply stated that it hewed to Centers for Disease Control and Prevention guidance, which recommends that healthy children be vaccinated.

That made Heather’s case a bit harder. Her lawyer argued that the kids had had their other vaccinations and were missing out on school and other social activities because they weren’t vaccinated against COVID-19.

Norm represented himself in court. He said he couldn’t afford a lawyer. He attempted to admit a range of evidence backing his case, but the judge refused some of it.

“That was something that definitely didn’t go the way that I thought it was going to go,” Norm said.

He had brought along pieces penned by vaccine-skeptical doctors, such as Marty Makary, arguing that COVID vaccines for kids had more risks than benefits. In the end, the judge admitted data Norm brought from the VAERS database maintained by the CDC, to which anyone can anonymously submit adverse vaccine side effects. He was also able to submit several Johns Hopkins studies looking into the effect of the vaccines on the menstrual cycles of women and girls.

Norm also noted that being pro-vaccine was a new position for Heather. In the past, she had been the one worried about vaccines, and had placed the kids on a delayed vaccine schedule when they were little because she was worried about potential long-term consequences. After their separation, Norm had them vaccinated right away.

Now, they’ve switched positions. Norm said he’s changed his mind because the COVID-19 vaccine doesn’t have a proven track record like the other vaccines recommended for school-age children do. Heather said her calculus shifted due to the urgency of the pandemic — plus, she has a decade of motherhood under her belt.

In her closing remarks, the judge said it was clear both parents cared very much about their children’s well-being, they just had different ideas of how to achieve it. She said she didn’t take these cases lightly.

The parents waited days for the judge to issue a decision. Heather said she was a nervous wreck, genuinely unsure which way the chips would fall.

It’s not clear how much of Heather and Norm’s complex history or the evidence they submitted was taken into account. In the end, the judge issued a simple order outlining the decision, with no explanation:

Heather would be granted decision-making authority on the matter of COVID-19 vaccination, but nothing else. She made appointments as soon as she got the order.

“It’s relieving news,” said Heather. “I didn’t think it was going to take over three months and close to $10,000. But here we are.”

The battle for their hearts and minds

It wasn’t an unambiguous win for Heather, though. The whole process took a toll on the kids. The push and pull between their mom and dad had made them skeptical of vaccines, and resentful of her. She had kept them in the loop the whole time: updated them that she and their father couldn’t agree, and that the decision was being made by a judge. She broke the news to them separately.

“My son is really sweet,” Heather recalled. “He curled up next to me on the couch and just sort of looked like, well, OK. He was very accepting, and it was very much his personality.”

Her daughter, on the other hand, did not take the news as well.

“She just looked at me and then looked out the window and said, ‘No, I’m not doing that.’”

According to Heather, that’s a function of her daughter’s personality, too. But it’s also the result, Heather thought, of her daughter being told she didn’t have to do anything to her body she didn’t want to.

“I had to stress in that moment, like, actually, sweetheart, you’re 9. Yes, you are,” Heather said.

It hurt to feel like her daughter had turned against her, but at the same time, that’s part of parenting, Heather said.

“You make difficult decisions to protect your kids all the time,” she said. “You disappoint them.”

Norm was also disappointed by the decision.

“It didn’t make sense to me when we started the conversation; at this point, it makes even less sense to me,” he said, noting that omicron infections had ebbed substantially, and that it was possible a new vaccine could be needed to target a future variant. Recent research also indicates that with omicron the Pfizer vaccine was much less effective in 5- to 11-year-olds than originally anticipated.

Still, Norm said, he had been careful to navigate the conflict without alienating his kids from their mother. He remains committed to that after the decision, as well.

“You read any book about divorce or co-parenting, and it’s always in bold caps-lock letters, ‘Do not disparage the other parent in front of the kids,’” said Norm. “So I’ve been very, very cognizant of that from the beginning.”

Heather said she’s set the same ground rule about Norm. But she does worry how this experience will affect her kids in the long term.

“How does that frame their critical thinking going forward? Do they then live in a limbo where they really never know what’s right?” she said she wonders. As a mother, she considers it her job to give her kids a moral compass.

“That’s hard when their hearts and minds get a little weaponized against what I believe to be a medically sound decision for them,” Heather said.

Norm is more confident that the experience will be a net positive for the kids. He said he thinks it will teach them to navigate conflict and accept differing opinions.

Heather took both children to get their first doses in early March. She hadn’t told them where they were going, and when they arrived at the pharmacy, she said, they felt ambushed and angry with her. She shrugged it off. Sometimes, she figured, this is just a mom’s job.

After the shots, which were painless and quick, her kids stuffed their pockets full of Dum Dums, and Heather took them to Chipotle. It may not have been exactly the celebratory moment she’d imagined, but as she watched them eagerly dig into their quesadillas, she felt that, for the first time in two years, she could finally exhale.