[Totally awesome question, coupled with a great overview of changes in lifespan over the last couple hundred years. -egg]
You may well be living your second life already. Have you ever had some health problem that could have killed you if you’d been born in an earlier era? Leave aside for a minute the probabilistic ways you would have died in the past—the smallpox that didn’t kill you because it was eradicated by a massive global vaccine drive, the cholera you never contracted because you drink filtered and chemically treated water. Did some specific medical treatment save your life? It’s a fun conversation starter: Why are you not dead yet? It turns out almost everybody has a story, but we rarely hear them; life-saving treatments have become routine. I asked around, and here is a small sample of what would have killed my friends and acquaintances: