Army Brig. Gen. Heidi Brown, shown here at the Pentagon: "Gender now shuts the door for me." David Gilkey/NPR hide caption

itoggle caption David Gilkey/NPR

Betsy Thompson (left) and her daughter, Kelly MacDonald, both decided to become soldiers. Courtesy of Betsy Thompson hide caption

itoggle caption Courtesy of Betsy Thompson

Retired Brig. Gen. Wilma Vaught at the Women in Military Service for America Memorial in Arlington, Va. David Gilkey/NPR hide caption

itoggle caption David Gilkey/NPR

Leigh Ann Hester, now a police officer in the suburbs of Nashville, Tenn., is the first female soldier since World War II to receive the Silver Star medal for valor in combat. David Gilkey/NPR hide caption

itoggle caption David Gilkey/NPR

Left: Brig. Gen. Wilma Vaught during her time serving in Vietnam; when she joined the military, she received training on how to put on makeup — but not how to fire a weapon. Right: An illustrated poster of Sgt. Leigh Ann Hester, the first woman since World War II to receive the Silver Star for valor. Both women are profiled in this series. Courtesy of Brig. Gen. Wilma Vaught; David Gilkey, NPR hide caption

itoggle caption Courtesy of Brig. Gen. Wilma Vaught; David Gilkey, NPR

U.S. soldiers return fire upon a sudden attack by Taliban on Combat Outpost Badel in eastern Afghanistan near the Pakistan border, Dec. 25. Rafiq Maqboold/AP hide caption

itoggle caption Rafiq Maqboold/AP

Defense Secretary Robert Gates (left) and Afghan President Hamid Karzai this month in Kabul. Musadeq Sadeq/AP hide caption

itoggle caption Musadeq Sadeq/AP

Defense Secretary Robert Gates speaks during a  news conference in Kabul on Wednesday. Gates visited Afghanistan to assess progress in the war. Musadeq Sadeq/AP hide caption

itoggle caption Musadeq Sadeq/AP