it's totally normal because people didn't start making it to 40 with regularity until very recently, thanks in part to synthetics. You are correct that synthetics have played a role in lengthening the human lifespan, but not as big of a role as people like to think. Mostly just eliminating mass diseases/plagues. In general, antibiotics are WAY over-prescribed and also very harmful. Really, the reason that we live longer today is because of our infrastructure. Food is widely available and regulated. We don't have to go around hunting and eating/drinking whatever we happen to find that day (risking all sorts of diseases, etc). Also, we don't get eaten by bears and lions and stuff as much anymore. The bottom line is that people get things like cancer, Alzheimers, diabetes, autism, food allergies, etc at astronomically higher rates today than ever before. It's because of all the toxins we put into our bodies. Boy... now I'm really off topic. The toxins taste really good so I will take the chance.