Back in the day, the unwritten rule of “women and children first” always used to govern who got a spot in a lifeboat, and who went stoically down with the ship. After all, 70 percent of the women and children on the Titanic were rescued, versus a mere 20 percent of the adult men. But then a 2010 study compared survival rates for the Titanic and the Lusitania and concluded that this chivalrous doctrine only prevailed in slow wrecks, when social norms had a chance to gain control of the situation. In fast descents, like the Lusitania’s 18-minute destruction, it was the fittest passengers, between the ages of 16 and 35, who had the best chance of survival. And now a new study deals another blow to “women and children first,” suggesting that this norm wasn’t normal at all.