Women have broken down many barriers in the military in recent years, but they are still not allowed to serve in the infantry and similar combat-arms specialties. However, for the first time, female soldiers have been taking part in infantry training to see how they respond to the intense regimen, USA Today reports.

The move brings women one step closer to yet another milestone, but it certainly won't be easy. The Marine Corps' Infantry Officer Course features a great deal of psychological and physical stress. So much so, in fact, that about 25 percent of all trainees don't make it through to completion.

The infantry, which is often on the front lines of combat, is the one of the last remaining hurdles for female soldiers. Though there are some critics of the Pentagon's move, the Department of Defense has been making more positions open to women over recent months. Earlier this year, the DoD made more than 14,000 positions available to women, according to the publication.

It's a smart move to open up more positions, given the role that female soldiers played in Iraq and Afghanistan. More than 280,000 women served in the two wars, many of whom found themselves in intense firefights and other combat situations, even though they weren't technically infantry members.