On July 26 at 3:35 p.m., after 16 grueling hours of climbing from Camp 4, Pasang Lhamu Sherpa, Dawa Yangzum Sherpa, and Maya Sherpa crested the 28,251-foot (8,611-meter) summit of K2, the second highest mountain in the world.

In doing so, the three Nepali women have laid claim to being the first all-female team to climb what many mountaineers consider a much tougher challenge than Everest.

"For us, it was our dream come true," Pasang Lhamu, 30, said in a telephone interview from Skardu, Pakistan, where the team arrived on August 2, after four days of hiking and driving from K2's base camp.

The feat was trumpeted in climbing circles as a breakthrough achievement for women in high-altitude mountaineering. Straddling the Chinese-Pakistani border in the heart of the Karakoram Range, 65 miles (105 kilometers) from the nearest village, K2 is regarded as one of the most difficult and dangerous peaks on the planet.

Only 18 of the 376 people who have summited K2 have been women, compared to the 372 women (of 4,034 climbers) who have stood atop Everest. For about every five people who have summited K2, one has died in the process, according to statistics provided by Eberhard Jurgalski, a K2 historian.

However, as details emerge about the Nepali women's climb, uncomfortable questions about the nature of their claim have begun to arise. Three male Sherpas accompanied the women to the summit, and the women climbed as a part of a larger guided group led by the trekking outfitter Seven Summit Treks, which included a male guide, six additional climbers (four of them men), and at least six more male Sherpas, all of whom also summited with the Nepali women.

It raises the question: What counts as an "all-female summit"?

"I don't think their accomplishment is diminished—it's just different," said Hilaree O'Neill, a professional ski mountaineer, who climbed Everest with Dawa Yangzum, 25, in 2012.

Questions about an expedition's true merit are not new to mountaineering. In 1978, Arlene Blum led the first successful American ascent of Annapurna with an all-female team. Her feat came under scrutiny due, in part, to the fact that male porters had supported her team. "Two years earlier in 1976, the American bicentennial Everest expedition ... was supported by 40 Sherpas. Does that diminish the climb being an American one?" Blum asked.

View Images Dawn Yangzum Sherpa took this photo of sunrise on K2, the world's second highest peak, on the way to the summit. Photograph by Dawn Yangzum Sherpa

Girl Power

From the outset, girl power has been central to the recent K2 expedition, which its planners called the "First Nepalese Women's K2 Expedition 2014." Pasang Lhamu, Dawa Yangzum, and Maya Sherpa, who are accomplished climbers (Pasang Lhamu and Dawa Yangzum are graduates of the Khumbu Climbing Center, and Maya Sherpa was the first Nepali woman to summit Cho Oyu), wanted to use their K2 climb as a vehicle to inspire women in their country and worldwide.

"We wanted to show women that if you just follow your dreams, even if you are a woman, you can do anything. Nothing is impossible," Pasang Lhamu said.

Nepali women have virtually no voice in the political, social, or domestic spheres.

"We're not talking about American or European women—we're talking about Nepali women, who have a very different sense of feminism and their place in the world and in mountaineering than, say, someone like myself," said O'Neill.

"It's still an amazing accomplishment because they have a lot of social constraints that they are overcoming, regardless if men were on it," she said.

K2's remoteness and difficulty make the need for support from porters even more crucial. Porters are commonly used in different capacities on expeditions, from cooking and carrying gear to fixing ropes on a route. Perhaps their biggest role is to maximize a climber's chances for success.

Mountain guide Arnold Coster, the husband of Maya Sherpa, who was in close contact with the women as they climbed K2, explained that the women's team operated independently within the Seven Summit team. "They made their own decisions, carried their own gear, but when it was summit time, the whole group had to work together," he said.

The fact that they teamed up with another group is not unusual. Terrain and weather generally dictate where and when teams move, so expeditions on many major mountains often blend together.

View Images The three team members (left to right, Maya Sherpa, Dawa Yangzum Sherpa, and Pasang Lhamu Sherpa) rest and refuel at Camp 4 at 7,850 meters. Photograph by Maya Sherpa

Male-Dominated Structure

Even if the Nepali women had wanted an all-female support team, it would have been nearly impossible. "The entire structure of Himalaya expeditions is 99.9 percent male-dominated, from the porters to the cooks to the waiters who serve and clean," O'Neill said.

However small the male Sherpas' involvement in the women's climb, for some, it changes the nature of the feat.

"I would personally not call it an all-female team or an all-female climb," said Kit DesLauriers, the first person to ski the seven summits. "All teammates are critical in a mountain endeavor, and in my book that barrier does not exclude hired climbing help."

She added, "I would not say it diminishes their accomplishment because that would be holding absolutely everyone to some base standard that is extraordinarily high, such as to do every climb without any assistance in any way whether Sherpa, porter, guide, oxygen."

However, some women do hold themselves to this extraordinarily high standard. Gerlinde Kaltenbrunner, the first woman to summit all of the world's 8,000-meter peaks without supplemental oxygen, is vigilant about refusing help from men, or any support at all, when tackling high-altitude objectives.

"In a team, for me, it is important as a woman that I am completely accepted like the men members and that I can carry the same-weight backpack as men," said Kaltenbrunner, who climbed K2, and the rest of the 8,000-meter peaks, without high-altitude porters. (Read the exclusive National Geographic account of her expedition.)

The ongoing debate about style isn't likely to be resolved soon. In the meantime, women will continue to advance the sport forward, moving toward the next frontier, which isn't all that different for them than it is for men, according to Conrad Anker, a three-time Everest summiteer.

"Probably the next thing for women alpine climbers is to go out and do demanding new routes," he said. "Repeating the standard route is great, but a new route on K2—and there's plenty of opportunities—by a woman would be a total breakthrough. Regardless of gender, that would be a remarkable thing."