When Teresa Siemann learned that she was pregnant with quadruplets, she felt a mixture of excitement and anxiety. It was 1989. Siemann, who was born in Brooklyn, worked, at the time, as an emergency-room nurse at New York Methodist Hospital, in Park Slope—she was no stranger to the oddities of pregnancy and unconventional medical situations. “Still, it was surreal,” she told me recently. “We didn’t know what to expect.” Her husband, John, meanwhile, thought of sports. “When I heard there were going to be four, I thought, We’ll practically have a basketball team,” he said.

Although they have forgone the N.B.A., those quadruplets—Brian, Amanda, Maria, and Jessica—will be running near their birthplace this fall, in the New York City Marathon. On November 6th, Brian will compete in the élite wheelchair competition, and his three sisters will run together in the corrals, with roughly fifty thousand other entrants. The twenty-seven-year-olds are believed to be the first quadruplets to compete together in the marathon’s history, according to New York Road Runners, the organization that has staged the event for forty-five years.

This has been a banner year for multiple-birth endurance athletes. At the 2016 Olympics, the Estonian sisters Liina, Lily, and Leila Luik—the “Trio to Rio”—became the first triplets to run in an Olympic marathon. Brian was in Rio, too, for his second Paralympic Games. Running in the New York City Marathon with his sisters was his idea: while training for his fifth attempt at the course, it dawned on him that all four were now capable of it. Maria and Amanda had run the Chicago Marathon together, and soon all three sisters were entering a variety of other races, including some half marathons. “New York presented an opportunity,” Maria said. “Why not tackle something new? And now that we’re older, and a bit more settled in our lives, after school? It just all fell into place.”

Clockwise from left: Maria, Jessica, Amanda, and Brian Siemann. Photograph Courtesy The Siemann Family Photograph Courtesy The Siemann Family

Getting here, though, was a long road. The Siemann quadruplets were born two months premature, and weighed about nine pounds combined. They spent their first two months in a neonatal intensive-care unit. When Brian was just a few days old, he suffered an injury to his spinal cord that left him paralyzed from the waist down. The four have an older brother, John, who is three years their senior. It wasn’t long before he was enlisted to help with the barrage of feeding, diapers, and related tasks of simultaneous childhood. “He was like my other pair of hands,” his mother said.

The family relocated to New Jersey to be closer to family; the elder John Siemann has worked on Wall Street for thirty years. He and Teresa dressed the kids in identical clothing—not to be cute but so they could keep track of them in crowds. “I didn’t want to lose one,” Teresa said. The siblings have not yet decided what they’ll wear on race day.

The parents didn’t push athletic endeavors on their children, but the kids quickly took to sports anyway. John, the oldest sibling, played ice hockey. The three daughters played basketball and softball in middle school. Maria and Amanda also played field hockey. Teresa said “that getting all of the kids to stuff was a sport of its own.” The G.M.C. Suburban that the family owned for many of the quadruplets’ schooling years accumulated more than three hundred and fifty thousand miles, she said. And being a mother of sports quadruplets elevated her soccer-mom status to another level in the New Jersey suburbs. “You just live in your car,” she said. “You don’t have much time for yourself. You live with a Crock-Pot and you have to be able to tell your kids that, sometimes, they’ll just have to eat cereal.”

Leading up to the race, the quadruplets have been swapping group texts and Facebook messages about their diets, their training plans, and their progress on long runs. Brian and Maria live in Illinois, not far from each other. Amanda lives in Connecticut, where, like her mother before her, she works as a nurse—in obstetrics. Jessica lives in Pennsylvania and works for a management-consulting firm. “I found it helpful as someone who is not a runner to be able to lean on them for advice,” Jessica said. “Things like what shoes to buy, what to do if my ankle is bothering me, if I had to miss a day for a work meeting. I’ve leaned on them as my cheerleaders.”

As a wheelchair competitor, Brian will start the race well ahead of his sisters, allowing him to relax and root for his sisters as they cross the finish line later in the morning. Their parents will be at the finish line, too. “It will be nice to have them all in the same place!” their father said.

John and Teresa are happy, too, that the course is dotted with biographically meaningful spots, most notably the stretch along Fourth Avenue, in Brooklyn, near where the kids were born. “As they go through the streets, I’ll know where they are,” John said. “It’s a home-town kind of thing.” The drive to and from the Verrazano-Narrows Bridge was once a regular schlep for Teresa and John on their trips to the city, including many visits to the doctor when their children were young. “It’s funny to me,” Teresa said. “That’s where the marathon course starts.”