Genetic Diseases Genetic diseases are concomitant with evolution. Most genetic diseases are an aberration of some biological maneuver present in health. Auto-immune diseases are the immune response turned wrong.
Obesity is a protective maneuver, to maximize food consumption during times of plenty, gone wrong.
Food stuffs do not spoil when packed around the ribs in the form of fat. Just so, all genetic diseases, when their cause is understood, can be seen to be a normal maneuver of the body gone wrong. These diseases are found in the animal kingdom too, and are not present in the human race for any particular reason beyond your ability to survive in spite of these diseases. In the animal kingdom, afflicted animals quickly die out. You protect your afflicted, allowing them not only to survive, but to propagate.