Editor’s Note: This article first appeared on The War Horse, an award-winning nonprofit news organization educating the public on military service. Subscribe to their newsletter.
Two months before Pete Hegseth appeared in front of Congress to testify in his confirmation to be secretary of defense, he sat across from the podcaster Shawn Ryan, talking about the Pentagon’s 2015 decision to open ground combat roles to women.
“It hasn’t made us more effective. It hasn’t made us more lethal,” Hegseth said. “I’m straight up just saying we should not have women in combat roles.”
By the time of Hegseth’s appearance on the show in late 2024, women had been serving in combat positions for nearly a decade across the military. The decision to integrate women had been thoroughly studied — before, during, and after the process — and thousands of women had served in roles ranging from infantry to combat engineers to special operations. The debate over women in combat was largely considered to be over.
But Hegseth was looking to reignite that debate. His book, “The War on Warriors,” which he was on the show to promote, dedicated a full chapter to the idea.
“Dads take us to push risks. Moms put the training wheels on our bikes,” he wrote in the book. “We need moms. But not in the military, especially in combat units.”
Hegseth softened his rhetoric during his January 2025 confirmation hearing, telling senators that women service members deserved the opportunity to serve in any role they qualified for.
“Women in our military, as I’ve said publicly, have and continue to make amazing contributions across all aspects of our battlefield,” he said.
Yet barely two months into his tenure at the Pentagon, Hegseth was already laying the groundwork to call into question those contributions. In March, he created a task force to review standards. Then, in December, the Pentagon’s personnel chief, Anthony Tata, announced a “review of the operational effectiveness” of ground combat units in the Army and Marine Corps, according to an internal memo obtained by The War Horse.
Now, that study is raising fears among military researchers and advocates for service women.
“We’re all concerned that this study is going to be used as a pretext to remove women from combat arms,” said Sue Fulton, the executive director of the Women in the Service Coalition, which advocates for women in the military.
Advocates have reason to worry: The researcher leading the current study on the issue, Jane Pinelis, helped lead a controversial review for the Marine Corps in 2015 that found mixed-gender units did not perform as well as all-male units. In his book, Hegseth drew heavily on that study to support the argument that women should not serve in combat arms.
“It was a flawed design from the get-go,” retired Army Col. Ellen Haring told NPR in 2015.
Defense officials initially assigned the current study to the Institute for Defense Analyses in December—only to change course and move the study to the Johns Hopkins University Applied Physics Laboratory, where Pinelis works, in April.
The highly unusual decision raises questions about the study’s independence, according to advocates and defense analysts.
“Why was this removed from IDA, where this kind of research is in their wheelhouse, and given to [the Applied Physics Lab], where this is clearly outside their expertise?” Fulton asked.
‘What is the problem we’re trying to solve?’
At his confirmation hearings, Hegseth told lawmakers that his concerns were not about women in combat, but rather, that standards had fallen to facilitate the integration of women in those units.
This February, after the Pentagon began its review, Sen. Mazie Hirono, a Democrat from Hawaii, asked the senior enlisted leaders from each military branch to testify on whether standards had been lowered. All of them said no.
“I’ve seen no data that supports that there’s been any lowering of standards or that there’s lowering of the readiness of units with those females in those units,” Navy Master Chief David Isom, a SEAL serving as the senior enlisted advisor to the chairman of the Joint Chiefs of Staff, testified.
Women who have served in combat roles agree.
“It becomes abundantly apparent very quickly if you are contributing to the team or detracting from the team when you have to move 40 ammo cans from point A to point B,” a female officer who served in the 75th Ranger Regiment told the military news website Task & Purpose earlier this year.
Even before combat units were integrated, women guarded convoys in Iraq and Afghanistan, accompanied special operations soldiers on missions, and frequently came under enemy fire.
“Women were already serving in combat,” said Rita Graham, the policy director at Service Women’s Action Network, an advocacy group for women in the military. The decision to open all combat roles to women came in part because four women service members, along with SWAN, sued the military for sex discrimination.
“They were being denied the recognition, the training, the medals, leadership opportunities, but most importantly, the career advancement,” Graham said.
Yet almost since he assumed office, Hegseth has been searching for evidence that standards have slipped.
Early on, Hegseth convened a team of advisors to evaluate standards at the Army’s Ranger School and special operations training programs. Hegseth served in Iraq with the team’s leader, Eric Geressy, who retired from the Army as a sergeant major. In “The War on Warriors,” Hegseth notes that Geressy was critical of women moving into frontline positions, which he called “chicken shit.”
The team quickly moved to lay the groundwork for a new study of women in combat, beginning with visits to Ranger School in March 2025 to “review and restore” standards, according to documents reviewed by The War Horse. Tata announced the study internally nine months later.
“Service members want a challenge[,] they do not want to be part of a loosing [sic] team and want to serve alongside the best,” a briefing document from the team’s visit to Ranger School said.
Laura Junor Pulzone, who served as the Pentagon’s principal deputy undersecretary for personnel and readiness as the military prepared for full gender integration in 2014, questioned whether a new study was even necessary.
“I was the readiness person,” said Junor Pulzone. “The only thing that mattered to me was making sure that we had a predictably ready force that was capable of executing the national defense strategy, full stop.”
“What I saw was an analytically based, sound way of doing this,” she said, noting that she would have raised red flags if she felt the military had not fully studied and prepared for the transition to gender-integrated combat units.
Gender-neutral standards for jobs open to men and women in the military were first required more than 30 years ago, as the military began training women to fly fighter jets. The same requirement held true for combat roles as they opened to women, and there is scant evidence that standards for those positions have declined in the past decade.
“This study has already been done,” Rep. Chrissy Houlahan, D-Penn., an Air Force veteran, told The War Horse. “We know that women who serve continue to perform and meet the same standards in ground combat as their male colleagues.”
Since 2015, thousands of women have served in Army ground combat units, and hundreds more have served in similar Marine units. Multiple women have completed Army Special Forces training and the Air Force’s special warfare training pipeline. More than 180 women have graduated from the Army’s Ranger School, one of the military’s most demanding combat leadership courses. And a recent Army study found that women who completed the course showed fewer signs of physiological stress at the end of training than men.
Researchers who spoke with The War Horse said a new study makes sense if at least some anecdotal evidence found problems in mixed-gender combat units. But that has not been the case, they said.
“What is the evidence of the problem?” Junor Pulzone said. “What is the problem we’re trying to solve?”
Researchers also told The War Horse the timeframe of the study — initially six months, though extended to a year when it was transferred to Johns Hopkins — was unusually compressed.
“If I were to set up doing a study like this, it would be a large mixed-methods [study]. There would be a lot of data from the past. There’d also be a lot of conversations that would have to happen—interviews, focus groups, which are going to require some pretty significant institutional review board proposals, as well as data-sharing agreements,” said another researcher who has studied women in the military extensively and who declined to be named over potential career impacts.
“It’s a very short time for a study like this.”
A controversial study
On its website, the Applied Physics Lab at Johns Hopkins lists 39 areas of expertise, ranging from “space technology” to “tactical and ballistic missile defense systems” to “cyber-physical security.” It does not list anything related to military readiness, personnel, or ground combat.
That has raised suspicions among military researchers, who told The War Horse they were surprised the Pentagon moved the study from the Institute for Defense Analyses to Johns Hopkins’ Applied Physics Laboratory. It’s unusual for the Pentagon to change the institution conducting a study, particularly in the middle of it, they said.
“Shopping around for researchers is not a good look,” Junor Pulzone said.
And the choice of the Applied Physics Laboratory struck researchers as especially unusual.
“They have robotics people, AI people, chemists. I don’t understand why they have [the study]. I really don’t. It doesn’t make any sense,” said one researcher, who spoke on condition of anonymity over fears of potential career impacts.
A Pentagon spokesperson declined to answer The War Horse’s questions on the record. But in a response provided on background, a Pentagon official said that after the study was assigned to the Institute for Defense Analyses, the Defense Department “recognized the need to incorporate combat-relevant field tests” into the assessment.
The Johns Hopkins Applied Physics Laboratory “has the capability to examine existing personnel and operational data, as well as conduct the field tests,” the official said.
The Applied Physics Laboratory did not respond to requests for comment.
“The Johns Hopkins Applied Physics Laboratory is a world-renowned research institution focused on artificial intelligence, robotics, and emerging scientific discoveries — no doubt vital and urgent work,” Houlahan said. “However, the Applied Physics Lab is not the first place that comes to mind when examining the role of women in ground combat.”
On Pinelis’ LinkedIn profile, the study’s lead researcher describes her current role as chief AI engineer at the Applied Physics Lab. She also lists work as the chief scientist for special operations. Years before, in 2015, as a statistician, she led the design and analysis of the Marine Corps study into gender-integrated units.
That study concluded that all-male units outperformed mixed-gender units on 69% of tasks. At its conclusion, the Marine Corps requested an exemption from the Pentagon’s directive to open all combat roles to women.
“This was a very politically unpopular conclusion,” Pinelis told an interviewer from Forbes in 2022. “There’s no room for compromise when it comes to scientific rigor.”
Pinelis did not respond to a request for comment from The War Horse.
The methodology behind the 2015 study drew sharp critiques. Critics pointed out that the units drew experienced male Marines, while female Marine volunteers had just gone through the Marine Corps’ initial nine-week infantry training course and only had to meet the minimum male physical fitness score to participate. It also evaluated women based on average scores, rather than assessing how capable individual female Marines were of meeting a standard.
“The fear is that something similar could happen,” said SWAN’s Graham, who previously served as an Army field artillery officer after the specialty was opened to women. “We’re really not opposed to an evidence-based review, if it’s done legitimately, if it’s done with the proper research questions, if it’s done with the proper sample sizes.”
In “The War on Warriors,” subtitled “Behind the Betrayal of the Men Who Keep Us Free,” Hegseth cites the study’s finding that female Marines were injured at a higher rate than male Marines as evidence that women should not serve in combat. But Marine Corps briefing materials on the study found that better screening for physical fitness would have eliminated that issue.
Critics also note that the Marine Corps’ summary of the study omitted findings favorable to mixed-gender units, which had better problem-solving skills, higher morale, and fewer disciplinary issues than all-male units.
Advocates for women in combat argue that Hegseth’s fixation on standards — which he often ties to physical fitness —reflects a limited understanding of the reality of modern combat, which requires soldiers to be flexible, solve complex problems, and increasingly demonstrate technical proficiency.
Designing a study to clearly answer the question of whether women should be in combat units is exceptionally difficult, said Michael McGurk, the former director of research and analysis at the Army’s Center for Initial Military Training, because so many issues come into play.
“How do you determine that women are the factor that’s causing the difference, and not the company commander’s leadership, the sergeant’s leadership?” he said. “You can always find the tactical reason why we shouldn’t do this.”
The future of combat
This March, Houlahan introduced a bill addressing the Pentagon’s decision to reexamine women in combat.
“Now more than ever, we should be supporting each and every servicemember willing to wear the uniform, not scrutinizing and pushing out qualified women simply because they are women,” Houlahan said in a statement.
The bill, called the WARRIOR Act, would prohibit gender-based exclusion in the military and ensure that positions have clear standards reflecting the needs of the job—not only physical requirements, but tactical, technical, and cognitive demands.
Advocates who spoke to The War Horse agree that not every woman is up to the task of serving in combat roles. But if the military is to operate as a true meritocracy, they argue, then everyone — men and women — should be given an opportunity to serve as long as they meet the high standards those jobs require.
“We can’t claim something as the Army’s premier leadership school, and say, well, you know, it’s only for leaders that are male,” said Thomas Stone, a former Army Ranger who oversaw training given to soldiers prior to Ranger School when women were first permitted to attend the course.
And as the nature of combat evolves, so do the skills required of a soldier to excel in it.
Stone pointed out that fitness standards — like the Army Ranger requirement to hike 12 miles with a 35-pound pack — are rooted in earlier conflicts, from a different time. He argued that focusing so much attention on a question of standards developed for older conflicts risks misunderstanding the requirements of a future conflict. The Pentagon, Stone noted, recently earmarked $54 billion for autonomous warfare in its upcoming budget.
“What does the future of war look like?” he said. “Don’t you want the best human being, regardless of gender, piloting that humanoid robot?”
