Members of a population may be prone to inherited genetic diseases if

Members of a population may be prone to inherited genetic diseases if inbreeding takes place frequently within the population.

Inbreeding is the production of offspring from the mating or breeding of individuals or organisms that are closely related genetically. By analogy, the term is used in human reproduction, but more commonly refers to the genetic disorders and other consequences that may arise from expression of deleterious or recessive traits resulting from incestuous sexual relationships and consanguinity.