As soon as doctors Vince and Vance Moss emerged from the chartered jet at Kabul International Airport, they were whisked through Afghan customs and escorted to a local security crew eager to help them with their medical supplies.

The Afghan greeters had never met the Mosses, but it wasn't hard to spot the tall, photogenic, identical twin surgeons from Philadelphia.

It was May, a temperate time for the 36-year-old brothers' second medical mercy mission to Afghanistan. Their first foray, during a mean winter a year earlier, had been an experiment: Could two gutsy Americans - both Army Reserve doctors acting as free agents on their own dime - go into isolated villages to treat sick and maimed civilians, without getting their heads blown off?

The brothers wanted to venture into even remoter areas on their second mission, now that they were familiar with the logistics, the terrain, the dangers.

After the Afghan guards loaded the medical supplies into a van, the brothers hopped in, and they took off.

At the back of the airport, the van suddenly stopped.

The "guards" pulled their guns, dumped the unarmed doctors, and departed with the antibiotics, painkillers, glucose meters, syringes, scalpels, and all the other provisions the twins had bought in the United States to supplement local supplies. In Afghanistan, where the average yearly income is $350, the stuff was worth a fortune.

"Our reputation preceded us," Vance said wryly as he and Vince sat in their Philadelphia condo late last month, showing photos of their courageous, crazy humanitarian odyssey.

For three months this year, that odyssey took them from the relative comfort, not to say safety, of the capital, Kabul, to the medieval conditions of mountainous outposts. They saw thousands of patients and operated on hundreds. As always, they did it side by side.

A perfectly matched pair

Vince, a cardiothoracic and trauma surgeon at Crozer-Chester Medical Center in Upland, and Vance, a urologist and kidney-transplant surgeon joining Crozer next month

, are a pair of a kind.

Their educational and career paths are almost as identical as their DNA.

They also share a passion for the military and, hokey as it sounds, for doing good. Growing up in lower-middle-class Marlboro, Md., they amassed Boy Scout merit badges the way other kids accumulated toys. They achieved the highest rank, Eagle Scout, at the youngest possible age, 14. Then they joined the Civil Air Patrol, the civilian auxiliary of the Air Force. In 1995, they joined the Army Reserve Medical Corps.

All of which helped prepare them to take on Afghanistan.

It began two years ago with a dilemma.

They had just finished fellowships in their surgical subspecialties, capping a decade of grueling medical training. Their practices in South Jersey were flourishing. And they were wrapping up a required four-month tour of duty in Stateside military hospitals.

That was when the Army asked the surgeons, both majors in the Reserve, if they would consider serving another tour - in Afghanistan.

Should they stay home and make a nice living doing what they had worked so hard for? Or should they jeopardize that by going to a country with a shattered infrastructure, a tattered economy, Taliban and al-Qaeda terrorists, narcotraffickers, civil strife, and relentless drought?

For the twins, it was a difficult decision.

"We tried to determine whether our practices could survive with us in Afghanistan or, if not, where should our commitment be at this time in our lives," Vince said. "And if we committed to go to Afghanistan with the Army, what would our duties be?"

In researching the answers, they heard heartbreaking stories from returning doctors who, under military rules, had to turn civilians away from U.S. medical facilities.

As a urologist, Vance was especially upset to hear about a 9-year-old boy with a urinary injury that could have been surgically repaired. The boy had been wounded and lost both legs when a land mine exploded while he played soccer.

The brothers petitioned to go to Afghanistan as Army doctors - but to treat civilians, not just U.S. soldiers.

"We wrote letters to a number of people in the Department of the Army explaining our mission," Vince said. "The reaction was, 'Great idea, Vince and Vance, but we can't support you fully on that because it's never been done before. We don't have any algorithm to work from.' "

One of their first operations during that maiden mission was on the 9-year-old amputee.

Their second mission

A few days after the airport setback that started their second trip, the twins traveled to an Afghan medical clinic in Jegdalek,

a dusty, dangerous town about 80 miles from Kabul, not far from the Pakistan border. They went with a driver, a translator, and Afghan security guards - this time real ones.

It was late afternoon when a father plopped his daughter's limp body on Vince's lap. She was about 2, with curly brown hair, frightened eyes, and hands wrapped in filthy bandages. She had a fever and a rapid, ragged heart rate - signs of a life-threatening infection.

She screamed in agony as Vince unwrapped her hands, which were severely burned and caked with dried, yellow pus. A tiny finger fell off as the doctors examined it.

How did she get hurt? Scalding water? A land mine? As usual, the brothers couldn't get straight answers.

Chaos and calamity are part of everyday life - and death - in Afghanistan. One in four children perishes before age 5, including many who don't survive birth. One in six women dies in childbirth, among the world's highest maternal mortality rates. On average, Afghans live only to age 43, the prime of life in the United States.

Vince put the girl on intravenous antibiotics and told the father to take her to the Afghan National Army Hospital in Kabul. She needed a proper operating room to debride the dead tissue.

The father was adamantly opposed. The Afghans won't treat her, he insisted. He refused to take her unless do ga na ge (pronounced doe-GA-na-ghee) went, too.

"We were like, 'You've got to be kidding me,' " Vince recalled. "But it turned out he was right.

"The Afghan doctors wanted money and promises from me and my brother in order to treat her. They said, 'Send me equipment.' Everything was money, money in order to treat this baby who was dying in front of us."

After 90 minutes of arguing, the brothers tried turning the tables.

"We said, 'If you won't let us treat your own countryperson here, we will gladly take her to the American hospital. And we will let them know what happened.' "

The Afghan doctors relented. The twins treated the girl. And she recovered.

Overachievers

What explains the Moss brothers' drive?

They credit their mother, Josephine Nelson, an oceanographer who works for the federal government, and their father, Haywood Moss, a retired prison corrections officer and Vietnam veteran.

The senior Moss, 58, became their primary caregiver when the boys were 4, after their parents divorced.

"They're overachievers," he said. "If you tell them, 'Go run for Congress,' they'd end up trying to be president. I never had to encourage them to study or achieve. In fact, there were times I'd try to slow them down, get them to sleep in on a Saturday."

Then again, from the time the boys were little, Moss prefaced conversations with them by saying, "When you become doctors . . ."

Another influence on Vince was Vance, and vice versa.

"People who don't understand what it's like to be a twin think it's odd that we did everything the same, that we had the same interests, the same passion for the same types of things," Vance said. "But believe me, we argue more than we agree about things. We're very competitive with each other."

By the time they received their undergraduate degrees from Pennsylvania State University in 1994, they had distilled their brand of gung-ho idealism. They recruited minority students to the bucolic campus. Founded a national campaign to combat youth crime and drug abuse. Fought tuition hikes by appealing to the trustees and then-Lt. Gov. Mark Singel.

Their self-confidence struck some as overconfidence.

"Our fraternity adviser discouraged us when we talked about med school," Vance said. "In fairness to him, our grades weren't that great."

So they hit the books. They wound up getting into seven of the 15 medical schools they applied to, and chose Temple University.

Earning the trust

While being

do ga na ge

meant the twins could never be inconspicuous, it also had its pluses.

"When we would go through these poppy fields and the drug lords would stop us, our concern was, 'Are they going to shoot us because think we're here to tell on them?' " Vince said. "But they would come up and already know who we are. They would say, 'Treat my family members first before you can go through.' "

Do ga na ge were also allowed to treat women and girls, even though, under Islamic law, women should not be seen, much less touched, by men other than their husbands.

"Our first trip, most of the people we treated were men," Vance said. "On the second trip, we stipulated we would see women and children first. Period."

It was the children - hordes of them everywhere - who captivated the twins. Of 30 million Afghans, half are younger than 16.

Vince recalled a baby who was struggling to breathe.

"We took an X-ray, diagnosed a diaphragmatic hernia, and repaired it," he said, pointing to a photo of a cherubic face beneath a knitted hat. "Her mother said that, for the first time, the baby started smiling. She had always been irritable because she was in respiratory distress."

Even more unforgettable was Khati Shafi, the 6-year-old son of their translator, Mohammad Shafi Faqirzada.

"My son's life . . . was miserable, as well as mine and my wife's, because in our society, having a defect like hypospadias is shameful," Faqirzada wrote in an e-mail for this article. "Sometimes his cousins were teasing him about it, and it hurt my wife's heart. Drs. Vince and Vance Moss changed our life."

Vance recognized that Khati's defect would require a series of operations - and more experienced surgeons. He called Edward Reda and Israel Franco, the pediatric urologists who oversaw his residency training at Westchester Medical Center in New York.

"They were out in the bush. They could have said, 'Let's just take this case and do what we can,' " Franco said by phone. "But they recognized their limitations. That shows a level of maturity. And that's what separates a good surgeon from a bad one."

Plans at Crozer-Chester

At Crozer-Chester Medical Center, Vince and Vance have ambitious goals. They plan to offer new minimally invasive surgical techniques. Increase African American organ donation. Even set up a kidney transplant program.

The fact that Crozer serves a poor, struggling, largely minority city is no coincidence.

For now, the brothers have no definite plans to return to Afghanistan. The Army, of course, could change that by activating them.

After the horrors they've seen, they understand why some people believe being a soldier is incompatible with doing good. But they have reconciled the paradox of their roles, just as they came to terms with treating all Afghans, innocent or malevolent.

"A lot of our friends who are opposed to the war ask us, 'Why are you in the military?' Well, my brother and I are military men first and foremost," Vance said as Vince nodded. "We serve our county and do whatever we're supposed to do. It's our patriotism. It's what drives us and gives us discipline. But at the same time, we're physicians. Our mission is to heal and save.

"So we have two roles."