Fitness, Mutational Load, and Eugenics

Abstract Eugenic arguments are not a thing of the past. In 2016, geneticist Michael Lynch published an article in Genetics arguing that human mental and physical performance are declining at a rate of 1% per generation. This estimate is not based on measurements of performance but on an argument from mutational load: Medical interventions are relaxing selection on the human population, which will lead to a buildup of deleterious mutations. This simple argument from mutational load is invalid. When the argument is made valid, it is not obvious that there are any significant consequences for human population health.