The breeding of people/ animals/ plants that are closely related to each other (first cousins or even closer), thus keeping the genepool weak and leaving them
vulnerable to various health
problems, mentally and emotionally as well as
physically.
Purebred dogs and royalty are notorious for inbreeding; to keep the line "pure" then they are only allowed to
procreate with their "own kind", even when offspring are stupid, sickly, deranged, ugly or any number of things.
Carlos II of Spain was the end result of the Spanish Hapsburgs; his parents were uncle and niece and both were highly inbred. Carlos was deformed, retarded, delicate, and had an extended infancy and premature senility. He was married twice, but he was impotent and sex was beyond his abilities.
Plants can be inbred, too; bananas of today are very different from those of three
generations ago and often lack the genetic
diversity which would keep them healthy.
