The future of access to abortion pills may turn on a basic legal question: Who has a right to bring a lawsuit?

Among the anti-abortion doctors involved in the case before the Supreme Court seeking to restrict availability of the pill is Dr. Christina Francis, who leads one of the anti-abortion groups suing the Food and Drug Administration to curtail distribution of the drug, mifepristone. She says she has experienced moral injury in treating patients who have taken the medication.

Left unclear is whether that reaches a necessary threshold to bring a lawsuit in federal court — that the plaintiffs would suffer concrete harm if mifepristone remained widely available. Lawyers call this requirement standing.

The F.D.A. “is forcing me to be complicit in an action that I have a moral objection to,” Dr. Francis, who is the head of the American Association of Pro-Life Obstetricians and Gynecologists, said in an interview on Friday.

Those statements are echoed by other anti-abortion doctors involved in the lawsuit, including an Indiana doctor and state legislator who has called for stronger punishments for abortion providers and a California doctor who helped pioneer an abortion pill reversal method that has not been supported by scientific evidence.

None of the anti-abortion doctors are required to prescribe the drugs or regularly treat abortion patients, but they say that they might encounter such patients in emergency rooms and that even treating side effects could cause them hardship. That, they say, would subject them to “enormous stress and pressure,” forcing them to choose between their consciences and their professional obligations.

The federal government and many legal experts contest those assertions. The government cites years of scientific evidence showing that serious complications from mifepristone are very rare, and experts express skepticism about the doctors’ claims of moral harm.

“It looks like a general objection to public policy,” said Elizabeth Sepper, a law professor at the University of Texas and an expert in conscience protections. “There are many things that our government does that violate each of our consciences. We might think, I don’t want to be involved in a state that administers the death penalty. But our legal system doesn’t allow us to go into court and say, I’m going to stop that public policy because it violates my conscience.”

The plaintiffs’ argument for standing may also run afoul of Supreme Court precedent.

A 2009 decision by the court, Summers v. Earth Island Institute, said that even if there was statistical likelihood of harm, it was insufficient for standing.

If the justices find that the standing claim fails, the case could be dismissed altogether.

The dispute has played out in the briefs filed to the Supreme Court.

Solicitor General Elizabeth B. Prelogar, arguing for the government, said that what scant evidence the challengers had supplied fell far short of showing real injury.

“Although mifepristone has been on the market for decades,” she wrote, the plaintiffs “cannot identify even a single case where any of their members has been forced to provide such care.”

“‘Stress and pressure’ are inherent” in the work of doctors, she added, contending that “simply being presented with a person in need of emergency care” did not qualify as injury to a doctor whose chosen responsibility was to treat patients.

Danco Laboratories, a manufacturer of mifepristone, warned that if the court decided the plaintiffs had standing, it could open the door to a flood of litigation from any doctor who disliked a drug or regulation, “destabilizing the industry and harming patients.”

Lawyers for the Alliance Defending Freedom, a conservative Christian legal advocacy group representing the doctors, noted that an appeals court said that the anti-abortion doctors and organizations had standing.

At issue in the case on Tuesday will be changes the F.D.A. made since 2016 that broadened access to mifepristone. Those decisions have allowed patients to obtain prescriptions for mifepristone by telemedicine and receive it through the mail.

The plaintiffs’ lawyers said those decisions escalated the risk that anti-abortion doctors “will see more women suffering emergency complications from abortion drugs.” Such complications, they said, include “retained fetal parts, heavy bleeding, severe infections,” which can inflict “mental, emotional and spiritual distress” on the doctors.

The federal government cites data showing that there was no increase in complications since the 2016 decisions and that serious complications occur in less than 1 percent of cases.

In her written declaration for the lawsuit, Dr. Francis said she had cared for a woman who experienced complications from taking abortion pills supplied by a website that shipped them from India. Asked why that would relate to decisions by the F.D.A., since it would not have approved or regulated the pills in question, Dr. Francis said she believed that its decision allowing American-based telemedicine providers to mail F.D.A.-approved pills was somehow also “allowing for women to be shipped drugs from India.”

Dr. Francis said in the interview that over the last two years, she cared for four or five patients who were bleeding, had infections or needed surgery to complete abortions.

The federal government, states and hospitals have established conscience protection policies to allow doctors and other health workers to opt out of providing care they object to — essentially establishing a route for anti-abortion doctors to avoid the harm they claim in the lawsuit. However, there is no evidence in the declarations, lawsuit or plaintiffs’ legal briefs that any of the doctors invoked conscience protections.

Dr. Ingrid Skop, another anti-abortion doctor who submitted a declaration, said in written responses to The New York Times that she had not invoked such protections. “The group where I practiced for 25 years had a policy not to perform abortions, so it was not an issue,” Dr. Skop said. In her current position, working a few shifts a month covering labor and delivery and the emergency room, if “a patient presents with an abortion-related complication, I will care for her,” she said.

Dr. Skop was an author on two recently retracted studies that suggested abortion pills were unsafe, both of which were cited by the plaintiffs in the lawsuit.

Dr. Francis said in the interview that often “in nonemergency situations, I have been able to excuse myself from patient care.” In emergency situations, she said, she felt “forced to violate my conscience.”

Although the anti-abortion doctors say mifepristone is unsafe for women, both Dr. Francis and Dr. Skop voiced no objection to the drug being used to treat women experiencing miscarriages. In a regimen identical to the medication abortion protocol, mifepristone is used for miscarriage treatment followed by misoprostol.

Dr. Francis said in those situations, she prescribed only misoprostol because she had not seen enough studies to know if using mifepristone first was more beneficial. “I don’t object to it on a moral basis,” she said.

Adam Liptak and Jodi Kantor contributed reporting. Julie Tate contributed research.