The real problem is much worse than most people understand. The actual number of mutations in humans is quite hight. We are ‘degrading’ as a species and the rate is higher than any hoped for genetic engineering could ever over come (though that won’t stopped scientist from trying). Good related interview b/w Dr. James Tour and Dr. John Sanford - Genetic Entropy & Genome Degeneration. A little long but worth the effort.
https://www.youtube.com/watch?v=i-y_dmi_oF4
Interesting to pair this with research that shows all species, including humans, seem to uniformly young based on mitochondrial DNA studies.