On February 25, 1852, the H.M.S. Birkenhead, an iron-hulled British troopship, steamed out of Simon's Bay, off the Western Cape of South Africa. The sea was calm and the day was clear. The Birkenhead carried around six hundred and thirty people in all: troops from ten regiments and a few of their family members, seven wives and thirteen children. It was bound for Algoa Bay, where the men were to join the colonial war against native Xhosa tribes. Early in the morning on February 26th, when all but the duty watch were asleep, the Birkenhead struck an uncharted rock, and then hit it once again. The rock sliced through the hull, and many of the soldiers who had been sleeping in their berths quickly drowned. The ship's captain, Robert Salmond, ordered that the anchor be dropped, the distress rockets fired, and the lifeboats lowered, and then he loaded all the women and children onto them. When the ship tore open and broke in two, Salmond cried out, "All those who can swim jump overboard, and make for the boats." But there were not enough boats, and only three of them could launch. Lieutenant Colonel Alexander Seton realized that the rush would swamp the lifeboats and drown the women and children in them. Drawing his sword, he ordered the men to stand fast. In the words of the 1852 Annual Register, "Under this heroic obedience to discipline the whole mass were engulphed in the waves by the sinking of the ship." Of the six hundred and thirty people who left the Cape, only a hundred and ninety-four survived—including every woman and child onboard.

The phrase "women and children first" did not appear until a few years after the Birkenhead went down, but the protocol dates to its evacuation. (Rudyard Kipling memorialized it as the "Birkenhead Drill" in his poem "Soldier an' Sailor Too.") Today, the call is most famously associated with the sinking of the Titanic; whatever the reference, the phrase evokes the courage and solemn fortitude of a man sacrificing himself for a lady. You could walk a steeds' path from this sentiment back to the Knights of the Round Table and their foresworn code of chivalry, as recorded by Sir Thomas Malory, "to always do ladies, gentlewomen and widows succor" and "to never force ladies, gentlewomen or widows." In 1857, five years after the Birkenhead sunk, the S.S. Central America went down on a voyage from Colón to New York. The magazine Godey's Lady's Book noted that "Captain Herndon's first order, 'Save the women and children!' was the test of this Christian heroism."

We may believe that we're beyond a publicly acknowledged code of male honor, and yet news reports of civilian deaths often follow the general toll with the number of women and children killed. Dispatches from the current war in Gaza have informed us that "half of Gaza's dead 'are women and children,' " that "many women and children among the dead," that "most of the injured were women and children." Offering the number of women and children dead underlines the vulnerability of the victims. This can be useful: it can help approximate the number of the dead who were actually combatants, a matter that is often in dispute. But it also invokes a continued belief that women, like children, need special protection. The phrase suggests a range, even a rank, of innocence among civilians, in which children and their mothers embody it most fully. It recalls the idea that wombs, the chambers that can repopulate a devastated group or nation, somehow make female bodies more holy. Of course, not all women are mothers, and men and women are equally vulnerable to aerial assault. If we truly wish to identify the most helpless victims, we should count, alongside children, the infirm and the elderly. Instead, we tally the number of women and children killed, reflecting and perpetuating outdated ideas about women's lives and women's bodies.

Early last year, Defense Secretary Leon Panetta lifted the military's ban on women in combat, saying, "If members of our military can meet the qualifications for a job, then they should have the right to serve, regardless of creed, color, gender, or sexual orientation." In November, four female Marines became the first women in Marine Corps history to complete infantry training, passing what many consider its most difficult test: a twelve-mile march with eighty pounds of gear in tow. This spring, William Denn, an Army captain and intelligence officer who has led soldiers in Iraq and Afghanistan, wrote in the Washington Post that women can be key assets in the field. Based on his patrols in Iraq from 2007 to 2009, Denn wrote, "Most Iraqi men were reticent to speak with us for fear of retribution from al-Qaeda. Iraqi women, often fed up with the violence in their neighborhoods, could be persuaded to provide information, but first we had to bridge the gender gap, build rapport and earn their trust, all of which took valuable time." Denn went on to write that "including women in front-line units would be more than an exercise in social equality; it would be a valuable enhancement of military effectiveness and national security."

Yet because we see female bodies as vulnerable and in need of protection, we often find it difficult to imagine them in combat or sustaining combat injuries. Last week, on the military Web site Ranger Up, a veteran named Lana Duffy wrote about the injuries she sustained after an I.E.D. explosion in central Iraq, including severe loss of eyesight, balance, and memory. "My arms were covered in bruises from the days of IVs and near-constant blood work," she wrote. "My face was mottled with healing black eyes from where the doctors had punched out the cartilage behind my nose to get access to that sweet spot in the middle of my head." But, when Duffy walked around Walter Reed Army Medical Center with her ex-husband, "no one seemed to notice it was my ex helping me walk and not the other way around. Instead he constantly got the question 'So where were you when you got hit?' while I heard, 'He looks great! Is he just here for follow up?' " In a war zone, we understand women as victims to be defended. (Or, alternately, to be exploited—the prevalence of sexual assault as a weapon of war cannot be overlooked.)

There is a persistent belief, Duffy continues, "that girls just don't get blown up." Women who have been wounded in war say they hear suggestions that they're just "being sensitive," that they're "unfit or less fit." Duffy makes the case for a military Leaning In: women need to be even tougher to show that they're fit enough. She writes, "Is it a double standard? Yes. Is it stupid and wrong? You bet. But instead of complaining about it, let's prove it. Meet the maximum standards if you want the job, regardless of the standard set. Hold yourself to a higher moral ground." Duffy's words suggest the immensity of the servicewoman's struggle against those who diminish the work and worth of women who join men on the battlefield. To do justice to those who risk everything, we better believe that "women get blown up, too."

Just as we have to squint our eyes to see a woman as a combatant, we have a hard time imagining a male civilian who is not, even informally, a fighter. What would happen if women, who we perceive as innocents in war zones, were understood to be simply war casualties, their worth neither more nor less than that of male civilians? Perhaps we would be more just and more respectful to female soldiers, and we would come a little closer to grasping the magnitude of each human loss.