The last two female Marines hoping to make their way through the Marine Corps' Infantry Officer Course as part of an experiment to integrate the program washed out on April 2, ending the research phase of the project.

The two were cut during the physically and academically demanding Combat Endurance Test, along with 81 of the 90 male Marines who applied for the program, Marine Corps Times reported April 8.

Female Marine officers who sought entry to IOC were not expected to meet the same physical fitness screening standards as male Marines, but they were required to match male performance in the course, Marine Corps spokeswoman Capt. Maureen Krebs told Military.com in November.

The 13-week school historically averages a 25-percent attrition rate.

During the first day's grueling Combat Endurance Test, Marines wear combat gear, perform various physical tasks and answer tactical questions while negotiating a land-navigation course, Krebs said.

The experiment began more than two years ago as part of a broader look at the possibility of opening ground combat specialties to women. Since then, 29 women volunteered for IOC at Quantico, Krebs said Friday.

Of the first group of 10 to volunteer for the course, nine failed to make it through the first day. The remaining female Marine dropped out a week later after being injured on the course.

Last October, three of the seven female volunteers made it through the Combat Endurance Test. Two of those who passed were captains. However, none of the women completed the program.

Of the two who washed out in April, one was a volunteer and the other was sent as a member of the Corp's recently integrated ground intelligence track. Though the IOC door has now closed for volunteers, women applying for ground intelligence officer slots will have to pass the program in order to attain that specialty, just like any male Marine would, Krebs said.

The Corps opened the ground intelligence officer specialty to female Marines in July 2013.

Data from the experiment will be compiled and analyzed. Marine Corps Commandant Gen. Joseph Dunford will use the analysis to issue a recommendation to Defense Secretary Ashton Carter on how the Corps intends to open up certain combat-arms jobs to women in 2016.

The Corps will also be studying the results of the gender-integration experiment at the Infantry Training Battalion course at Camp Lejeune, North Carolina, where enlisted female Marines have had greater success.

As of February, 122 of the 358 women who entered the course graduated. Women, however, who successfully completed the program were not awarded the infantry military occupational specialty, Krebs said.

The Corps will also consider data gleaned from the Ground Combat Element Integrated Task Force it established last May to research integrating women into combat jobs. The task force is modeled along the lines of a battalion landing team. Women volunteers are trained in ground combat arms skills and integrated into combat units, with a research team observing performance.

-- Bryant Jordan can be reached at bryant.jordan@military.com