Had you been a woman traveling in second class on the Titanic a century ago, your chances of survival were quite favorable — 86 percent were saved. For the men in second class, one of whom was my grandfather Lawrence Beesley, the odds were the reverse — only 14 percent survived, and the rest were drowned in the freezing waters of the Atlantic.

Notions of male chivalry toward the weaker sex have since been cast aside, and it is no longer de rigueur for a man to yield his seat on a bus, or a lifeboat, to someone of the opposite sex. But in the Edwardian era it was a moral code with a force stronger than law. When the order was given on the Titanic for families to be separated and for women to board lifeboats first, no man rushed ahead.

I have often wondered how my grandfather managed to beat the heavy odds against his survival. But I was too young, while he lived, ever to ask such an impertinent question. I have since come up with a possible answer, based on many readings of “The Loss of the Titanic,” a book he wrote within a few weeks of his rescue.

My grandfather earned first-class honors in science at Cambridge University and had discovered a new species of algae before he graduated. But instead of pursuing a career in science he chose to become a high school physics teacher in his home town, Wirksworth, in northern England. Perhaps he needed the steadier income — he was already married to his first wife and had a young son, Alec (who was to marry Dodie Smith, the playwright and author of “101 Dalmatians”).