(From another answer I wrote in this thread) Think of dental braces. In old times, without orthodontics, misaligned teeth would be a visible marker of less than optimal fitness. Ugly. Negative selection pressure. As orthodontics becomes more prevalent, in the beginning lots of people get a beauty boost. Celebrate! Yet, in a few generations, a larger and larger fraction of the population now needs more and more sophisticated dental braces. Teeth simply don't fit on the mandible anymore, because there is no selection force to prefer people with good teeth as marriage partners. Everybody has visibly good teeth! We can keep this illusion going with technology, but it's a growing problem. Should we close orthodontics clinics tomorrow? Probably not, but that should not prevent us from recognizing the long term hidden costs of medical technology. Use sparingly, mostly for emergencies.