Jim Michaels

USA TODAY

WASHINGTON — Three years after the Pentagon ordered the military services to prepare to open all ground combat jobs to women, few of them have expressed interest in a career in the infantry or other newly opened positions.

As part of an experimental program, 233 women who completed Marine Corps infantry and other ground combat schools are eligible for those jobs, but none has requested a formal transfer.

The Army sees similar results. “We’re not expecting a high propensity for infantry or armor,” said Lt. Col. Jerry Pionk, an Army spokesman.

The Marine Corps initially expected about 200 women a year to enter jobs previously closed to women, including a small number in the infantry.

Defense Secretary Ashton Carter said opening the jobs would improve combat effectiveness because the military would draw from a larger pool of applicants for the infantry and other specialties.

“To succeed in our mission of national defense, we cannot afford to cut ourselves off from half the country's talents and skills,” Carter said.

Military officials said the interest among women in previously all-male jobs may change over time, citing the gradual progress in expanding earlier opportunities for women in the military. “Incrementally over time, it’s been one success after another,” Pionk said.

It remains to be seen whether this time will be different. The infantry, in particular, is a job that requires carrying heavy loads over great distances and living in austere conditions for long periods. The life of an infantryman has changed little over the course of U.S. military history.

The armed services are also opening artillery, tanks and other specialties, which may prove less of an obstacle for women.

Three years ago, then-Defense secretary Leon Panetta ordered the services to open ground combat jobs to women by 2016. Carter approved the services' plans this year, which allowed women to start training and entering the jobs.

It may be an additional year before women show up in infantry units, since recruits who express interest in the jobs will need to undergo training in those occupations.

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The Marine Corps, an infantry-centered force that serves long deployments aboard ships, requested an exception for infantry, citing a study that showed infantry units with women did not perform as well as all-male units.

Carter denied the Marine request this year, saying there would be no exceptions. The Marines pledged to successfully implement the order.

Women have engaged in combat in Iraq and Afghanistan and have flown combat aircraft for years but had been barred from infantry, armor, Special Forces and other jobs that require the most physical strength and endurance.

The Marine Corps and Army, which have the bulk of ground combat jobs, have conducted extensive studies to create “gender neutral” physical tests and have codified the physical requirements of the jobs.

The services say they are taking a number of steps to ensure a smooth transition and are committed to making the transition without hurting readiness. “There’s no doubt we’re leading cultural change,” Marine Brig. Gen. James Glynne said.

The Marine Corps said it will move women into positions within infantry battalions to help mentor female Marines who may eventually enter the units.

The service said it is sending training teams to bases around the world to begin an initiative to help with the transition. The initiative will address issues such as “unconscious bias,” Marine Col. Anne Weinberg said.

All the services have developed “gender neutral” physical screening tests for applicants and pledged that standards will not change.

Those standards are rigorous. No woman has completed the Marine Corps’ rigorous Infantry Officer Course, although 29 women have tried. Three women have graduated from the Army’s Ranger School.

Women graduate from the Army Ranger School in 2015:

Officials acknowledged that they don’t know how many women will be interested in the jobs. “We don’t think there’s going to be a lot,” said David Brinkley, an official at the Army's Training and Doctrine Command, which oversees the analysis of job requirements. "But to be honest, there’s not a lot of men who want to do that either,”