Why women outlive men — almost everywhere on Earth

In virtually every country on record, women live longer than men — the global gap is roughly five years, and it holds across rich and poor nations, war and peace, even historical famines. This is one of the most consistent patterns in all of human biology, yet its cause is a tangle of nature and behavior.

One clue comes from a study of cloistered monks and nuns by demographer Marc Luy. Monastery residents share remarkably similar lives — same schedules, meals, no smoking, little risky behavior. There, the survival gap between men and women shrank to about a single year. That suggests most of the everyday five-year gap comes not from biology alone but from behavioral and social differences: men historically smoke more, drink more, take more physical risks, work more hazardous jobs, and see doctors less.

Biology still plays a real part, though. Women carry two X chromosomes, giving a genetic 'backup copy' when one gene is faulty; estrogen appears to protect blood vessels; and women tend to mount stronger immune responses. The lesson isn't that men are doomed — it's that a large slice of the gap is made of modifiable habits, not destiny.